A Guide to DNS Settings for Cold Email Deliverability

Data center server racks managing the DNS settings for cold email deliverability.

You’ve crafted the perfect email, built a targeted list, and hit send, only to see your open rates flatline. It’s a frustratingly common story, and the culprit often isn’t your copy or your offer. The problem is technical, and it’s happening before anyone even has a chance to read your message. Your emails are getting flagged as suspicious and sent straight to the spam folder, or worse, blocked entirely. This is where the right DNS settings for cold email become your most valuable asset. These records—SPF, DKIM, and DMARC—are the foundational trust signals that prove your legitimacy to inbox providers. Without them, you’re essentially showing up uninvited. This guide will walk you through setting them up correctly.

Key Takeaways

Prioritize Your Authentication Records: Correctly configuring SPF, DKIM, and DMARC is the most critical technical step for cold email. These records act as your domain's ID, proving to email providers that you're a legitimate sender and keeping your messages out of the spam folder.
Start Your DMARC Policy with Monitoring: Always begin your DMARC implementation with a p=none policy. This allows you to gather reports and see who is sending email from your domain without accidentally blocking your own legitimate messages. Only move to stricter policies once you're sure everything is configured correctly.
Treat DNS as an Ongoing Process: Your DNS settings aren't a one-time setup. Regularly use diagnostic tools to check your records and review DMARC reports to catch errors or unauthorized activity. This proactive maintenance protects your sender reputation and prevents future deliverability issues.

What Are DNS Settings and Why Do They Matter for Cold Email?

Think of your DNS settings as the digital handshake between your sending domain and your recipient's inbox. It’s the first impression you make, and it happens entirely behind the scenes. Before anyone even reads your subject line, their email provider is checking your domain's credentials to decide if you’re trustworthy. For anyone running cold email campaigns, this is everything. Without the right DNS setup, your carefully crafted messages might never even get a chance to be seen, landing straight in the spam folder or getting blocked completely.

Getting these settings right tells the world—and more specifically, email providers like Google and Microsoft—that you are who you say you are. It’s the technical foundation that proves your emails are legitimate and not sent by a malicious actor spoofing your domain. While the acronyms might seem intimidating at first, understanding what they do is the first step toward building a strong sender reputation and ensuring your outreach campaigns actually reach their destination. It’s less about being a tech wizard and more about putting the right security measures in place to protect your domain and your deliverability. We'll break down exactly what you need to know to get it right.

A Quick DNS Primer

So, what exactly is DNS? The Domain Name System (DNS) is essentially the phonebook of the internet. Humans remember names, like scaledmail.com, while computers communicate using numbers, called IP addresses. DNS is the system that translates those easy-to-remember domain names into the numerical IP addresses needed to locate a server on the internet. When you send an email, your server performs a DNS lookup to find the correct mail server for your recipient's domain. It’s a fundamental process that makes sure your message knows where to go. Without it, we’d all have to memorize long strings of numbers just to send an email.

How DNS Affects Email Deliverability

This is where things get really important for your campaigns. Correctly configured DNS records are your ticket to the inbox. If they’re missing or set up incorrectly, email providers see it as a major red flag, and your deliverability will suffer. The three most critical records for email authentication are SPF, DKIM, and DMARC. Together, they form a powerful security trio that verifies you are a legitimate sender. Think of them as your domain's ID, signature, and security policy, all rolled into one. Implementing them correctly, especially DMARC, can significantly improve your delivery rates—sometimes by as much as 5-10%—by proving your emails are authentic and trustworthy.

The Essential DNS Records for Cold Email

Think of DNS records as the technical handshake that happens behind the scenes before your email ever lands in an inbox. It's how your domain introduces itself and proves it's trustworthy. Without this proper introduction, you're basically showing up to a party uninvited—and you'll likely be shown the door (or the spam folder).

For cold email, this isn't just a nice-to-have; it's the absolute foundation of your deliverability. Getting these settings right tells mailbox providers like Google and Microsoft that you're a legitimate sender, not a spammer trying to impersonate a domain. It’s your first and best line of defense against the spam filter.

There are four key records you need to get right: SPF, DKIM, DMARC, and Reverse DNS (PTR). Think of them as a team working together. SPF creates the approved sender list, DKIM signs and seals the message to prove it’s authentic, DMARC sets the rules for what to do if the first two checks fail, and Reverse DNS confirms your server is who it says it is. Setting them up correctly is a one-time task that pays dividends on every single email you send. We'll walk through what each one does and why it's so critical for your outreach campaigns.

SPF: Give Senders Permission

SPF, or Sender Policy Framework, is the most basic form of email authentication. Think of it as the official guest list for your domain. This simple text record in your DNS tells the world which mail servers are authorized to send emails on your behalf. When an email arrives, the recipient's server checks your SPF record to see if the sending server's IP address is on the list. If it is, the email passes the check.

If the IP address isn't on your list, it’s a major red flag. This is how SPF helps prevent domain spoofing, where spammers send emails that look like they came from you. By clearly defining your authorized senders, you make it much harder for anyone to impersonate your domain and damage your reputation.

DKIM: Verify Your Email's Identity

DKIM, which stands for DomainKeys Identified Mail, acts as a digital tamper-proof seal on your emails. It adds a unique cryptographic signature to the header of every message you send. This signature is generated using a private key that only your sending server knows. The corresponding public key is published in your DNS records for anyone to see.

When a receiving server gets your email, it finds your public key and uses it to verify the signature. A successful DKIM check confirms two crucial things: that the email was actually sent from your domain and that the message content hasn't been altered in transit. This provides a much stronger layer of authentication than SPF alone, proving the integrity of the message itself.

DMARC: Protect Your Domain's Reputation

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is the supervisor that tells receiving servers what to do based on the results of SPF and DKIM checks. It’s a policy you publish in your DNS that instructs servers on how to handle emails that fail authentication. You can tell them to do nothing (p=none), send the message to spam (p=quarantine), or block it entirely (p=reject).

But DMARC’s real power comes from its reporting feature. It sends you detailed reports about which emails are passing and failing authentication checks, giving you incredible visibility into your email ecosystem. These DMARC reports help you spot unauthorized use of your domain and troubleshoot deliverability issues, making it an essential tool for protecting your sender reputation.

Reverse DNS (PTR): Confirm Your Server's IP

While most DNS records link a domain name to an IP address, a Reverse DNS record—also known as a PTR record—does the opposite. It maps your sending server's IP address back to its associated domain name. This is a critical security check for many email providers. When your email arrives, the receiving server performs a "reverse lookup" on the IP address it came from.

It then checks if the resulting domain name matches the one you're sending from. If there's no PTR record or if the names don't match, it looks highly suspicious and can cause your email to be flagged as spam. For anyone using a dedicated sending infrastructure, ensuring your PTR record is correctly configured is a fundamental step in establishing your server's legitimacy and building trust with mailbox providers.

How to Set Up Your SPF Record

Setting up your SPF record is the first essential step in authenticating your domain. Think of it as creating a public guest list for your domain’s email. It tells receiving mail servers, like Gmail and Outlook, exactly which IP addresses and services are authorized to send emails on your behalf. This simple TXT record is your first line of defense against spammers who might try to impersonate your domain to send malicious emails, a practice known as spoofing.

When a server receives an email claiming to be from you, it does a quick check of your SPF record. If the sender’s IP address is on your list, the email gets a green light. If it’s not, the server becomes suspicious, which often means your email gets flagged as spam or rejected outright. Getting this right is a non-negotiable for cold outreach. It builds a foundation of trust with inbox providers, signaling that you’re a legitimate sender. While it might sound technical, the process is usually straightforward and involves adding a single line of text to your domain’s settings. We’ll walk through exactly how to do it.

Create Your SPF Record

First things first, let's be clear on what an SPF record does. SPF stands for Sender Policy Framework, and it’s a crucial DNS record that specifies which mail servers are permitted to send emails for your domain. It acts as a safeguard against email spoofing and is a fundamental piece of improving your email deliverability. By creating this record, you’re essentially publishing a list of approved senders. This makes it incredibly easy for receiving email systems to verify that a message truly came from you. Without it, there’s no way for them to know if an email is legitimate or a forgery, making it much more likely your campaigns will land in the spam folder.

Understand SPF Syntax

The syntax of an SPF record looks a bit like code, but it’s quite simple once you know what you’re looking at. Every record is a single line of text that starts with v=spf1. What follows are the "mechanisms" that define your authorized senders. For example, you might see include:_spf.google.com if you use Google Workspace or ip4:192.168.1.1 to authorize a specific server IP. The record ends with a qualifier like ~all or -all. This tells receiving servers how strictly to treat emails from senders not on your list. The good news? You rarely have to write this from scratch. Your email sending service will provide the exact record you need to use.

Add the SPF Record to Your DNS

To put your SPF record to work, you need to add it as a TXT record in your domain's DNS settings. You’ll do this through your domain registrar (like GoDaddy or Namecheap) or wherever you manage your DNS. The process varies slightly between providers, but the core steps are the same. You’ll navigate to your DNS management page, select the option to add a new record, and choose "TXT" as the record type. For the "Host" or "Name" field, you'll typically enter "@" to apply it to your root domain. Then, you’ll paste the entire SPF string provided by your email service into the "Value" or "Content" field and save your changes.

How to Configure Your DKIM Record

Think of DKIM (DomainKeys Identified Mail) as a digital wax seal on an envelope. It adds a unique, tamper-proof signature to every email you send, proving to receiving servers that the message is genuinely from you and hasn't been altered along the way. This is a massive trust signal for providers like Gmail and Outlook, and it's a critical piece of the puzzle for keeping your cold emails out of the spam folder.

Setting up DKIM is a fundamental step for anyone serious about email outreach. It tells the world that your domain is legitimate and that you stand behind the emails you send. The process might sound technical, but it’s mostly a straightforward copy-and-paste job. You’ll generate a special key from your email provider, add it to your domain’s settings, and you’re good to go. Let’s walk through exactly how to get it done.

Generate Your DKIM Keys

First, you need to generate your DKIM keys. This process creates a unique pair: a private key that stays with your email provider to sign outgoing messages, and a public key that you’ll publish for the world to see. You’ll almost always do this from your email provider’s admin dashboard. For example, if you use Google Workspace, you’ll head into the Admin console to find the email authentication settings and generate a new record. Your provider will give you the exact text you need for the next step, so just follow their instructions.

Publish the DKIM Record in Your DNS

With your public key in hand, it’s time to publish it in your domain’s DNS settings. This is usually managed wherever you bought your domain name, like GoDaddy, Namecheap, or Cloudflare. Log in to your domain registrar’s website and find the DNS management section. From there, you’ll create a new TXT record. Your email provider will give you two pieces of information to copy and paste: the Host (or Name) and the Value (which contains your public key). It’s crucial to copy these values exactly as they appear to ensure everything works correctly.

What a DKIM Record Looks Like

So what does this jumble of text actually look like? A DKIM record is just a TXT record with a specific format. The Host/Name part usually looks something like selector._domainkey.yourdomain.com. The Value is a string of text containing different tags. For example, you’ll see v=DKIM1 to indicate the version and p= followed by a long string of characters—that’s your public key. You don’t need to memorize the syntax, but seeing the structure helps demystify it. Just focus on copying the record precisely as your email provider gives it to you.

How to Implement a DMARC Record

Putting a DMARC record in place is the final step in the email authentication trifecta, and it’s a powerful one. It acts as the enforcer, telling receiving mail servers what to do with emails that fail SPF and DKIM checks. Implementing DMARC isn't a one-and-done task; it's a process you'll want to approach in stages to avoid accidentally blocking your own legitimate emails. By starting with a monitoring policy, you can gather valuable data on who is sending email from your domain before you start telling servers to reject or quarantine messages. This careful, step-by-step approach ensures you protect your domain's reputation without disrupting your business operations. Let's walk through how to do it safely and effectively.

Choose Your DMARC Policy

Your DMARC policy tells email providers how to handle messages that claim to be from your domain but fail authentication. You have three options: none, quarantine, and reject. Your first step should always be to start with p=none. Think of this as a "monitoring-only" mode. It won't affect your email delivery at all. Instead, it asks servers to send you reports about your email activity, showing you which messages are passing and which are failing authentication checks. This is the most critical phase because it gives you the visibility you need to ensure all your legitimate sending services are correctly configured before you get stricter. You can find a great breakdown of DMARC policies to understand the nuances of each setting.

Create Your DMARC Record

A DMARC record is a simple text (TXT) record that you add to your domain's DNS settings. It contains a few key instructions for mail servers. At a minimum, your first record should include the version, your chosen policy, and an email address for receiving reports.

Here’s what a basic starting record looks like: v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com

v=DMARC1: This just identifies the record as a DMARC record.
p=none: This sets your policy to the monitoring-only mode we just discussed.
rua=mailto:dmarc-reports@yourdomain.com: This is crucial. It tells servers where to send the aggregate reports. Make sure this is a real inbox you can access. You can use a free DMARC record generator to help build this string correctly.

Roll Out DMARC Safely

Once your p=none policy is active, you’ll start receiving reports. These reports are your roadmap. They show you every service sending email on behalf of your domain. Your job is to review them and make sure every legitimate sender (like your email marketing platform or your CRM) is passing both SPF and DKIM checks. If you see a legitimate service failing, you need to fix its SPF or DKIM configuration before moving on.

Only after you’re confident that all your real emails are authenticating properly should you consider a stricter policy. The next logical step is moving to p=quarantine, which tells servers to send failing emails to the spam folder. After monitoring that for a while, you can finally move to p=reject to block unauthenticated emails completely. Rushing this process is a common mistake that can cause your own emails to get blocked, so take your time.

Common DNS Mistakes That Hurt Deliverability

Setting up your DNS records is a huge step, but a few common slip-ups can undo all your hard work and send your emails straight to the spam folder. Think of it like building a house—the foundation can be perfect, but if a window is installed incorrectly, you’ll still get leaks. These mistakes are surprisingly easy to make but, thankfully, just as easy to fix once you know what to look for. Let’s walk through the most frequent errors so you can avoid them and keep your deliverability strong.

Using Multiple SPF Records

This is one of the most common and critical mistakes you can make. You should only have one SPF record for your domain. When an email server checks your domain, it looks for a single, clear set of instructions. If it finds multiple SPF records, it gets confused and doesn't know which one to trust. This confusion often leads to a "PermError" validation result, and many email providers will simply reject your email as a precaution. It’s like having two different entries for your address in a directory—the mail carrier won’t know where to deliver the package. Always consolidate all your sending services into a single SPF record to provide a clear, authoritative source.

Common DKIM Setup Errors

When it comes to DKIM, the strength of your cryptographic key matters. A frequent error is using a key that’s too short. Your DKIM keys should be at least 1024 bits long, but using a 2048-bit key is even better for security. Shorter keys are more vulnerable and can be compromised, which damages your sender reputation and deliverability. Think of it as the difference between a simple password and a complex one. A stronger key provides better security and builds more trust with inbox providers. Always opt for the longer key length when your email service provider gives you the choice.

DMARC Policies That Backfire

DMARC is powerful, but it can cause major problems if you’re too aggressive too soon. A big mistake is setting your policy to p=reject right from the start. This tells receiving servers to block any email that fails authentication, which could include legitimate emails from services you forgot to authorize. The best approach is to begin with a p=none policy. This "monitoring-only" mode lets you collect DMARC reports and see who is sending emails on your behalf without impacting delivery. Once you’re confident that all your legitimate mail is authenticating correctly, you can gradually move to stricter policies like p=quarantine and eventually p=reject.

Forgetting Reverse DNS

Reverse DNS (rDNS), also known as a PTR record, is like a caller ID for your mail server. It confirms that your server's IP address is legitimately associated with your domain name. Many email providers, especially larger ones like Gmail and Microsoft, automatically check for a valid rDNS record. If they can’t find one, or if the IP address and hostname don’t match, they often see it as a sign of a spammer trying to hide their identity. This can cause your emails to be blocked outright. Ensuring your server has a valid PTR record is a simple but essential step for proving your legitimacy to inbox providers.

How to Check if Your DNS Settings Are Correct

After you’ve gone through the work of setting up your DNS records, it’s tempting to call it a day. But the most critical step is still ahead: verification. Think of it like proofreading an important email before you hit send. A single typo or misplaced character in your DNS settings can send your deliverability plummeting, causing your carefully crafted emails to land in spam or get blocked entirely. You need to be absolutely sure that internet service providers (ISPs) are seeing the records exactly as you intended.

The good news is you don’t have to guess. There are plenty of free, easy-to-use tools that act as a second pair of eyes, confirming that your SPF, DKIM, and DMARC records are published and working correctly. Running these checks takes just a few minutes, but it can save you from weeks of troubleshooting deliverability headaches down the road. It’s a simple quality check that ensures your technical foundation is solid before you start sending your cold email campaigns. Taking the time to verify your setup is one of the smartest things you can do to protect your domain’s reputation and maximize your outreach success.

Tools to Test Your DNS Setup

You don’t need to be a technical wizard to confirm your DNS records are correct. The easiest way to check your work is with a diagnostic tool. Websites like MXToolbox offer a suite of free tools that let you see what mail servers see when they look at your domain. You simply enter your domain name, and the tool will perform a lookup for your SPF, DKIM, and DMARC records. It will show you the exact record it finds and often flag common errors, like syntax mistakes or having multiple SPF records. This gives you instant feedback on whether your records have propagated and are configured properly.

Verify Your SPF, DKIM, and DMARC

Getting your DNS records right is absolutely essential for cold email. If they aren't set up correctly, your emails are likely to be flagged as suspicious and sent straight to the spam folder. The three most important records—SPF, DKIM, and DMARC—work together as a system of checks and balances. SPF declares which IP addresses are allowed to send email for your domain, DKIM adds a digital signature to verify the message hasn't been tampered with, and DMARC provides instructions on what to do if an email fails either of those checks. Verifying that all three are correctly published in your domain's DNS settings is the cornerstone of building email trust.

Monitor Your Email Authentication

Setting up your DNS records isn't a one-time task. Think of it as an ongoing maintenance project to protect your domain's health. Your main tool for this is your DMARC reports. These reports give you valuable insight into who is sending emails using your domain name. By reviewing them regularly, you can confirm that your legitimate emails are passing authentication checks and, more importantly, spot any unauthorized activity. If someone is trying to spoof your domain, your DMARC reports will show you. This ongoing monitoring helps you catch issues early and maintain a strong sender reputation over time.

Warning Signs Your DNS Needs a Fix

Even with the perfect email copy and a curated prospect list, your campaign can fall flat if your technical setup isn't right. DNS issues are often the silent campaign killer, but they leave clues. If you’re not getting the results you expect, don't immediately blame your subject lines. Your DNS settings might be sending up red flags that are easy to miss if you don't know what to look for. Paying attention to these warning signs can help you catch problems early and get your emails back on track to the inbox. Let's walk through the three biggest indicators that your DNS records need a little TLC.

Your Emails Keep Landing in Spam

This is the most obvious and frustrating sign. You spend hours crafting the perfect message, only for it to land in the spam folder. If your open rates have plummeted, this is the first place to investigate. Proper DNS setup is critical for cold email because records like SPF, DKIM, and DMARC are your first line of defense against spam filters. They prove to receiving mail servers that you are a legitimate sender. Without them, you look suspicious, and your emails are far more likely to be flagged as junk. If your campaigns are underperforming, check your DNS records before rewriting a single word of copy.

You're Seeing Authentication Failures

Authentication failures are a direct signal that something is technically wrong. You might see these in your bounce-back messages, with notes about SPF alignment or DKIM signatures not validating. It’s a more common problem than you might think—many companies don't configure their email authentication correctly on the first try. These errors are a server's way of telling you it can't verify that your email is legitimate. Paying attention to your DMARC reports is the best way to spot these issues. They provide a clear overview of which messages are failing authentication checks, giving you a road map for what to fix.

Your Domain Gets Blacklisted

Landing on a blacklist is the worst-case scenario. When this happens, your messages are blocked outright by major email providers, bringing your campaigns to a halt. This is precisely why you should never use your main business domain for cold email. A few spam complaints can tarnish your domain's reputation, affecting deliverability for your entire company. With providers like Google and Yahoo now requiring DMARC for bulk senders, the stakes are higher than ever. You can check if your domain is on a blacklist, but the best strategy is prevention through proper DNS configuration and a dedicated sending domain.

How to Maintain Healthy DNS Settings

Setting up your DNS records is a huge step, but the work doesn’t stop there. Think of your DNS settings like a garden; they need regular attention to stay healthy and productive. Over time, you’ll add new tools, switch email providers, or change your sending infrastructure. Without occasional check-ups, your records can become outdated, leading to authentication failures that send your carefully crafted emails straight to the spam folder.

Maintaining your DNS settings is all about protecting your domain’s reputation and ensuring your emails consistently reach the inbox. It’s a proactive strategy that prevents deliverability problems before they start. By creating a simple maintenance routine, you can keep your sending reputation strong and your outreach campaigns effective. The good news is that it doesn’t have to be complicated. Focusing on a few key practices—like regularly reviewing your records, analyzing your DMARC reports, and being strategic with subdomains—will keep your email program running smoothly. Let’s walk through how to make each of these a simple part of your workflow.

Review Your DNS Records Regularly

It’s easy to treat your DNS setup as a one-time task, but it’s crucial to check in on your records periodically. Your business evolves, and your tech stack often changes with it. You might add a new marketing automation tool or stop using an old service, and each of these changes can impact your DNS. An old SPF record pointing to a service you no longer use can cause confusion, while forgetting to add a new sender can lead to immediate deliverability issues.

Make it a habit to review your DNS records at least once a quarter or whenever you add or remove a service that sends email on your behalf. A quick audit helps you confirm that all your records are accurate, up-to-date, and correctly formatted. This simple check-up ensures that all your legitimate email streams are properly authenticated and helps you spot any unauthorized services that might be using your domain.

Read Your DMARC Reports

If you’ve set up DMARC, you’re already collecting a goldmine of data about who is sending email from your domain. These reports are your security guards, showing you every single source—legitimate or not—that’s using your domain to send mail. While the raw XML files can be a bit intimidating, there are many tools available that can help you visualize DMARC data and make sense of it all.

Start by setting your DMARC policy to p=none. This "monitoring mode" allows you to gather reports without risking any of your legitimate emails being blocked. By reading these reports, you can verify that your known sending services (like ScaledMail and your marketing platform) are passing authentication. You can also spot any unauthorized senders trying to spoof your domain, giving you the information you need to tighten your policy and protect your brand.

Use a Smart Subdomain Strategy

Not all emails are created equal, and your domain reputation strategy should reflect that. Instead of sending all your email—transactional, marketing, and cold outreach—from your main domain, it’s much safer to use separate subdomains. For example, you could use outreach.yourcompany.com for cold email campaigns and updates.yourcompany.com for customer notifications. This is a powerful way to practice reputation isolation.

This strategy protects your main domain’s pristine reputation. If your cold outreach subdomain experiences a dip in reputation (which can happen with high-volume sending), it won’t affect the deliverability of your crucial transactional emails. This separation gives you more control and resilience, ensuring that one email stream doesn’t negatively impact another. It’s a simple structural change that can significantly improve your overall deliverability and campaign performance.

How to Troubleshoot Common Delivery Issues

Even with a perfect setup, you can sometimes run into frustrating delivery issues. It happens to the best of us! The good news is that most problems have a straightforward solution. When your emails aren't landing where you want them to, a few targeted checks can usually uncover the culprit. Think of this as your go-to checklist for diagnosing and fixing the most common DNS-related hiccups that can throw your cold email campaigns off track. We’ll walk through what to do when your emails hit the spam folder, how to handle propagation delays, and some quick fixes for authentication errors.

What to Do When Emails Still Go to Spam

It’s incredibly frustrating to do everything right and still see your emails land in spam. If this is happening, the first step is to go back to basics. Setting up your DNS records correctly is the foundation of your deliverability. A tiny mistake here can cause your emails to get flagged or blocked entirely.

Start by using a diagnostic tool to double-check that your SPF, DKIM, and DMARC records are all valid and passing. Pay special attention to DMARC—it’s no longer just a good idea; major email providers now require it for bulk senders. If your records check out, the issue might lie elsewhere. Consider your email content, your sending volume, or the quality of your email list.

Solve DNS Propagation Delays

After you update a DNS record, the change isn't instant. It has to "propagate" across servers worldwide, which can take anywhere from a few minutes to 48 hours. If you’re in a hurry, there’s a trick to speed things up. Before you make a change, lower the record’s TTL (Time to Live) to 300 seconds (5 minutes). Once you confirm the change is live, you can raise it back up. This tells servers to check for updates more frequently, helping your changes spread faster. You can use a DNS propagation checker to watch your updates go live across the globe in real time.

Quick Fixes for Authentication Errors

Authentication failures are often caused by small syntax errors in your DNS records. These records are what prove to receiving servers that your emails are legitimate, so getting them right is essential for landing in the inbox. If you’re seeing errors, run through these common culprits:

SPF: Your SPF record can’t have more than 10 DNS lookups. If you use multiple services that need to be included, you might hit this limit. Make sure you’ve flattened your record or are using a subdomain strategy to stay under the cap.
DKIM: A common mistake is a simple copy-paste error. Double-check that your public key is entered correctly and that there are no extra spaces or missing characters.
DMARC: Always include a monitoring email address in your DMARC record (using the rua=mailto: tag). Without it, you won’t receive the reports that tell you how your emails are performing.

If you’ve checked these and are still stuck, it might be time to get an expert opinion.

Frequently Asked Questions

Do I really need all three records—SPF, DKIM, and DMARC? Yes, you absolutely do. Think of them as a three-legged stool for your email reputation. SPF creates an approved list of senders, DKIM adds a tamper-proof seal to your messages, and DMARC tells email providers what to do if the first two checks fail. If one is missing, the stool is wobbly. Having all three in place sends a powerful signal to providers like Google and Microsoft that you are a serious, legitimate sender who takes security seriously.

I use my main company domain for cold email. Is that really a problem? It's a significant risk. Your main domain's reputation affects every email your company sends, from sales quotes to customer support replies. Cold outreach naturally carries a higher risk of spam complaints, which can damage that reputation. By using a separate domain for your outreach campaigns, you create a firewall. If your outreach domain runs into any trouble, the deliverability of your critical business emails remains safe and sound.

How long does it take for these DNS changes to start working? After you add or update a DNS record, it can take anywhere from a few minutes to 48 hours to become active across the entire internet. This is called propagation. While the technical change can take time, the impact on your sender reputation is gradual. You won't see a magical jump overnight, but with each successfully authenticated email you send, you build more trust with inbox providers, leading to better deliverability over time.

What's the biggest mistake people make when setting this up? The most common and damaging mistake is rushing the DMARC setup. It’s tempting to jump straight to a strict p=reject policy to block spammers, but this can backfire and block your own legitimate emails. The safest approach is to start with a p=none policy. This puts you in a monitoring-only mode, allowing you to collect reports and see exactly what's being sent from your domain before you start telling servers to block anything.

Can I break my regular email if I make a mistake with these settings? It's a valid concern, but it's unlikely you'll cause a major outage if you're careful. The biggest risks come from typos or being too aggressive with your DMARC policy too soon. Always double-check the records you copy and paste from your email provider, and use a free online tool like MXToolbox to verify your setup. As long as you follow the process step-by-step, especially by starting DMARC in monitoring mode, you can avoid disrupting your normal email flow.