5 Common DMARC Issues and How to Fix Them

Fixing common DMARC issues on a computer with email and security padlock icons.

Think of your DMARC record as the passport control for your email domain. It checks the credentials of every message claiming to be from you and decides whether to let it through, send it for further inspection, or deny entry altogether. When it’s working correctly, it keeps imposters out and ensures your legitimate messages travel freely. However, a small error in your paperwork—a misconfigured record—can cause major delays or even get your own emails rejected at the border. Many of these holdups are caused by a handful of common dmarc issues. This guide will act as your diplomatic guide, helping you identify and fix these problems so your emails can clear customs and arrive safely in the inbox every time.

Key Takeaways

DMARC is your email authentication enforcer: It works on top of SPF and DKIM, giving you control to block fraudulent emails, protect your brand's reputation, and improve your overall deliverability.
A gradual rollout is the only safe approach: Always begin with a monitoring policy (p=none) to identify all your legitimate sending services. Only move to stricter quarantine or reject policies after confirming you won't block your own campaigns.
Think of DMARC as a living policy, not a one-time task: As you add new email tools, your authentication needs will change. Regularly review your DMARC reports to authorize new senders and ensure your configuration remains effective.

What is DMARC? (And Why You Should Care)

Think of DMARC as the official security policy for your email domain. It’s a system that tells the world’s email servers, “Only emails that are really from me are allowed through. If you see anything suspicious, here’s what you should do with it.” DMARC, which stands for Domain-based Message Authentication, Reporting & Conformance, is your first line of defense against people trying to impersonate your brand.

Why should you care? Because without it, anyone can send an email that looks like it came from your company. This opens the door for phishing scams and spam campaigns that can ruin your brand’s reputation and get your domain blacklisted. For anyone running outreach campaigns, a solid DMARC policy isn't just a nice-to-have; it's essential for protecting your deliverability and ensuring your messages land in the inbox. It’s a key tool to protect your email domain, your brand, and your customers' trust from fake emails.

How DMARC Protects Your Emails

DMARC works by giving you control over how receiving email servers handle messages that claim to be from your domain but fail authentication checks. You set a policy that tells servers to either monitor these emails (p=none), send them to the spam folder (p=quarantine), or block them entirely (p=reject). This means you get to decide the fate of fraudulent emails, effectively stopping scammers from using your domain to trick your customers or prospects. DMARC offers several policy settings that dictate how receiving email servers should handle emails that fail authentication. It also provides reports, giving you valuable insight into who is sending email on your behalf—both legitimate and fraudulent—so you can make informed decisions.

How DMARC, SPF, and DKIM Work Together

DMARC doesn’t work alone. It’s the final piece of a three-part email authentication puzzle, standing on the shoulders of SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail). Think of it this way: SPF is like a guest list that tells servers which IP addresses are allowed to send email for your domain. DKIM is like a tamper-proof seal that verifies the message hasn't been altered. DMARC is the security guard who checks for a valid name on the guest list or an unbroken seal, and then enforces the rules. DMARC needs either SPF or DKIM to pass, and they must "align" with your email's "From" address. If your SPF and DKIM records aren't set up correctly, DMARC can't do its job.

The Real Cost of a Bad DMARC Setup

Ignoring DMARC or setting it up incorrectly can have serious consequences. When your domain isn't protected, it becomes a prime target for cybercriminals. "Without a functioning DMARC policy, unauthorized emails that appear to be from your domain may be sent," warns UpGuard. These spoofing attempts can be used for phishing attacks, malware, and other malicious activities. For your business, this translates into more than just a security headache. It means your legitimate emails are more likely to be marked as spam, your sender reputation plummets, and the effectiveness of your entire email outreach strategy is compromised. The trust you've built with your audience can be damaged in an instant, making a proper DMARC setup non-negotiable.

Spot Common DMARC Configuration Errors

Setting up DMARC can feel a bit like assembling furniture without instructions—it’s easy to end up with a few screws loose. The good news is that most DMARC issues stem from a handful of common configuration mistakes. Once you know what to look for, you can spot and fix them quickly. Let’s walk through the most frequent errors so you can get your record working correctly and protect your domain.

Incorrect Syntax and Policy Values

It might sound basic, but a simple typo is one of the most common reasons a DMARC record fails. DNS records are picky, and one wrong character can make the entire entry invalid. For example, misspelling quarantine as quarintine will cause receiving mail servers to ignore your policy completely. Another frequent mistake is using outdated terms; the monitor value was used in early drafts of DMARC but has since been replaced with none. If your record contains these kinds of errors, it’s not doing anything to protect you. Always double-check your syntax and ensure you’re using the correct, current policy values to avoid these common DMARC mistakes.

Multiple Records and Wildcard DNS Issues

When it comes to DMARC, there can be only one. Your domain’s DNS settings should contain a single DMARC TXT record. If you have more than one, email servers won’t know which one to follow and may ignore them all, leaving your domain unprotected. This often happens when different team members or platforms try to add a record without realizing one already exists. Similarly, wildcard DNS records can cause problems. A wildcard might cause a DNS lookup for your DMARC record to mistakenly return a different record, like an SPF entry, leading to authentication confusion. You can understand email authentication limits to see why having just one record is a strict rule.

Domain Alignment Problems

This is where many people get tripped up. DMARC doesn’t just check if SPF and DKIM pass—it checks for alignment. In simple terms, the domain in your email’s "From" address (the one your recipients see) must match the domain used in your SPF and DKIM authentications. If they don't align, DMARC will fail, even if SPF and DKIM pass on their own. For example, if you send an email from yourdomain.com through a third-party service that uses its own domain for SPF checks, you’ll have an alignment failure. This is one of the most critical DMARC problems because it directly impacts the deliverability of your legitimate emails.

Subdomain Policy Misconfigurations

Securing your main domain is a great first step, but don’t forget about its subdomains. Attackers know that subdomains are often less protected and will exploit them to send phishing emails that look legitimate (e.g., from billing.yourdomain.com). A common misconfiguration is setting a weak subdomain policy, like sp=none, while your primary domain has a strict p=reject policy. This essentially leaves a backdoor open for spoofers. To close this gap, you need to apply a specific and secure policy to your subdomains (sp=quarantine or sp=reject) once you’re confident that all your legitimate subdomain mail is authenticating correctly.

Third-Party Sender Integration Mistakes

Most businesses use multiple services to send emails, from marketing platforms and CRMs to customer support tools. Each of these third-party senders must be properly authorized to send email on your behalf. If you start using a new service and forget to add it to your SPF record or set up DKIM for it, the emails it sends will fail DMARC checks. This is the leading cause of legitimate emails being blocked or sent to spam. The key is to maintain a complete inventory of all your sending services and ensure each one is correctly configured in your DNS. A DMARC fail often points directly back to a misconfigured third-party sender.

Your Toolkit for DMARC Validation

Fixing DMARC issues doesn't have to feel like you're fumbling in the dark. A handful of specialized tools can shine a light on your configuration, helping you spot errors and understand how your emails are being treated by receiving servers. Think of these as your DMARC support system, designed to translate technical jargon into clear, actionable insights. Whether you need a quick syntax check or a comprehensive monitoring platform, the right tool can make all the difference.

Most of these tools are built to be user-friendly, so you don’t need a deep technical background to get started. They automate the process of checking records, parsing reports, and testing your authentication. By adding a few of these to your workflow, you can move from guessing what’s wrong to knowing exactly what to fix. This proactive approach is key to maintaining strong deliverability and protecting your domain’s reputation. Let’s look at the four main types of tools you’ll want to have on hand.

Record Checkers

A DMARC record checker is your first line of defense. It’s a simple diagnostic tool that instantly validates your DMARC record to ensure it’s formatted correctly and published properly in your DNS. Just enter your domain, and the tool will fetch your record, check for syntax errors, and confirm that your policy values (like p=none or p=reject) are valid. This is the fastest way to catch common mistakes like typos or incorrect tags. Many platforms offer a free and user-friendly DMARC diagnostic tool that gives you an immediate pass-or-fail result, making it an essential first step in any DMARC troubleshooting process.

Report Analyzers

Once your DMARC record is active, email providers will start sending you reports about your email traffic. These raw DMARC reports are XML files and are notoriously difficult to read. That’s where a report analyzer comes in. These tools ingest those complex reports and transform them into visual, human-readable dashboards. You can see which servers are sending emails from your domain, whether those emails are passing or failing authentication checks, and which ones are legitimate versus potentially fraudulent. This insight is crucial for safely moving your policy from p=none to a stricter enforcement level without blocking your legitimate email streams.

Authentication Testers

While a record checker confirms your DMARC syntax, an authentication tester verifies that your entire email authentication setup (SPF, DKIM, and DMARC) is working together correctly. These tools provide an address where you can send a test email. Once received, the tool analyzes the email’s headers to check its SPF and DKIM alignment and see how it measures up against your DMARC policy. It’s a practical way to simulate how a receiving mail server sees your emails. Using an all-around deliverability tool can give you confidence that your legitimate emails are properly authenticated before you tighten your DMARC policy.

Monitoring Platforms

For a more hands-off, long-term solution, a full monitoring platform is the way to go. These platforms combine record checking, report analysis, and often authentication testing into a single, ongoing service. They continuously process your DMARC reports, provide historical data, and send you alerts when new sending sources or potential threats appear. This allows you to monitor your records and manage your email ecosystem without having to manually check reports every day. For any business that relies heavily on email, a dedicated monitoring platform is an invaluable asset for maintaining domain security and optimal deliverability.

How to Fix Your DMARC Configuration

Once you’ve identified a problem with your DMARC setup, the next step is to fix it. It might seem technical, but breaking it down into smaller steps makes the process much more manageable. Most issues come down to a handful of common mistakes that are straightforward to correct. By methodically checking your record, aligning your authentication, and accounting for all your sending services, you can get your DMARC policy working correctly to protect your domain and improve your email deliverability.

Validate and Correct Your Record Syntax

The most frequent cause of DMARC failure is a simple typo. A misplaced comma, an incorrect tag, or even a hidden character can invalidate your entire record. Start by carefully reviewing your DMARC TXT record in your DNS settings. Every DMARC record must begin with v=DMARC1;. From there, check that each tag is spelled correctly and followed by an equals sign. If you’re listing multiple email addresses for reports, they must be separated by a comma with no space, and each address after the first needs its own mailto: prefix. Using a DMARC record checker is a great way to automatically scan for these kinds of syntax errors.

Resolve Authentication Conflicts

DMARC works by checking that your emails align with your SPF and DKIM authentication. A DMARC fail often means your SPF or DKIM records aren't set up to match the "From" address your recipients see. This is a common issue when you use third-party services for marketing or customer support. These platforms send emails on your behalf, but if they aren't properly authorized in your DNS, their messages will fail authentication. The key is to ensure the domain used for SPF and DKIM authentication aligns with the domain in your visible "From" address. This tells receiving mail servers that the third-party service has your permission to send emails for you.

Adjust Your Policy Parameters

Your DMARC policy tells email providers what to do with unauthenticated mail. To get real protection, your policy tag (p=) must be set to either quarantine or reject. A policy of p=none only monitors email and offers no defense against spoofing. While starting with p=none is a good first step, the goal is to move to a stricter policy. Also, make sure the tags in your record are in a logical order. While the order isn't strictly enforced for all tags, having the version and policy tags (v= and p=) at the beginning is a standard practice that prevents confusion and potential processing errors by some receivers.

Manage Third-Party Senders

If you use tools like Mailchimp, Salesforce, or Google Workspace to send emails, you have to account for them in your DNS records. Forgetting to do so is a primary reason for DMARC failures. Start by making a complete list of every service that sends email using your domain. Each of these services will provide specific instructions for setting up SPF and DKIM. You’ll need to add their information to your domain’s DNS records. This process authorizes them as legitimate senders, ensuring the emails they send on your behalf pass DMARC checks and land in the inbox.

Handle Your Subdomain Configuration

It’s easy to focus on securing your main domain (like yourcompany.com) and completely forget about your subdomains (like info.yourcompany.com). By default, a DMARC policy set on your main domain doesn't automatically apply with the same strictness to its subdomains. This leaves them vulnerable to spoofing. To fix this, you can add a subdomain policy tag (sp=) to your DMARC record. For example, adding sp=reject tells receivers to reject unauthenticated mail from any of your subdomains. This closes a common security loophole and ensures your entire domain ecosystem is protected.

How to Implement DMARC the Right Way

Getting DMARC right isn't about flipping a switch; it's a careful process. Rushing into a strict policy can accidentally block your own legitimate emails, which is the last thing you want when you're running outreach campaigns. The key is to be methodical. By following a clear, step-by-step approach, you can protect your domain from spoofing without disrupting your email flow. Think of it as building a strong foundation before you put up the walls. Let's walk through the right way to get it done.

Start in Monitoring Mode

Your first step is to set your DMARC policy to p=none. This is known as "monitoring mode," and it’s a non-negotiable starting point. With this policy, you’re telling email providers to send you reports on all emails—both legitimate and fraudulent—that claim to be from your domain, but you aren't asking them to block anything yet. It’s purely for data collection. This allows you to see who is sending email on your behalf (including all your third-party services) without any risk of interrupting your legitimate mail flow. You get a complete picture of your email ecosystem before you start making enforcement decisions.

Deploy Your Policy in Stages

Once you’ve spent some time in monitoring mode and understand your email sources, you can begin to enforce your policy. But don't jump straight to the strictest setting. The best practice is to move through the policies gradually. Start by changing your policy to p=quarantine. This tells receiving servers to send unauthenticated emails to the spam folder instead of outright blocking them. It’s a safer intermediate step. After you’ve confirmed that only illegitimate emails are being quarantined, you can confidently move to p=reject. This final policy instructs servers to completely block any email that fails DMARC checks, offering the strongest protection for your domain.

Align Your Authentication

One of the most common DMARC issues is a lack of alignment. For DMARC to pass, the domain in your email's "From" address must match the domain used in your SPF and/or DKIM records. If they don't match, it's a failure, even if SPF and DKIM pass on their own. This often happens when using third-party email services that send from their own domains. You need to ensure these services are configured correctly to achieve DMARC alignment. Think of it like a package delivery: the return address on the box (SPF/DKIM) needs to match the sender's name on the label ("From" address) for the recipient to trust it.

Perform Regular Maintenance

DMARC isn't a "set it and forget it" task. Your email ecosystem changes over time as you add or remove software and services. That's why ongoing maintenance is critical. You should be reviewing your DMARC reports regularly—at least once a month—to spot new sending sources or potential authentication issues. This also includes periodically rotating your DKIM keys to maintain security. Consistent monitoring ensures your DMARC policy remains effective and accurately reflects your current sending practices, keeping your legitimate emails flowing and your domain secure.

Advanced DMARC Management Strategies

Once you’ve moved past the initial setup and troubleshooting, you can start thinking more proactively about your DMARC strategy. It’s not just about fixing errors; it’s about creating a resilient system that protects your domain reputation and keeps your emails landing in the inbox. This means shifting from a reactive stance to a proactive one where you’re consistently monitoring, optimizing, and managing your email authentication. This advanced approach is what separates a basic setup from a professional one that can handle serious email volume and protect your brand's integrity at scale.

For businesses that rely on high-volume outreach, this advanced management is non-negotiable. It’s how you maintain high deliverability and ensure your messages reach their intended audience, campaign after campaign. By adopting these strategies, you can turn DMARC from a simple security measure into a powerful tool for managing your entire email ecosystem. It’s about fine-tuning your setup to support your growth and protect your brand over the long term. Instead of just preventing spoofing, you'll gain deep visibility into your email channels, identify misconfigurations before they cause delivery failures, and build trust with inbox providers. This is how you ensure your infrastructure is an asset, not a liability. Let’s walk through what that looks like in practice.

Analyze Your DMARC Reports

Think of your DMARC reports as your email security dashboard. These reports are invaluable tools that show you exactly who is sending emails from your domain—both legitimate and fraudulent sources. By regularly analyzing these reports, you can spot authentication failures, identify unauthorized senders, and get a clear picture of your email deliverability. This data allows you to make informed decisions instead of guessing what’s wrong. You’ll see which third-party services are aligned correctly and which ones need their SPF or DKIM settings adjusted, helping you maintain a clean sending reputation.

Optimize Your Infrastructure

Your DMARC policy is only as strong as the foundation it’s built on. That foundation is your SPF and DKIM setup. For DMARC to work effectively, you need to make sure your SPF and DKIM records are correctly configured and aligned with your domain. This means double-checking that all your legitimate sending services are included in your SPF record and that DKIM signatures are passing authentication checks. Regularly testing your setup confirms everything is working as it should and prevents legitimate emails from failing DMARC checks, which is crucial for any high-volume campaign.

Manage Multiple Domains

If your business operates more than one domain, you need a DMARC strategy for each one. It’s a common misconception that one record can cover everything, but you can only have one DMARC record per domain. Each domain sends email and has its own reputation, so it requires its own tailored DMARC record. This is especially important for companies with different brands or regional websites. By implementing a unique DMARC policy for each domain, you ensure that all your email streams are protected and properly authenticated, preventing gaps in your security.

Set Up Automated Monitoring

Manually sifting through raw DMARC reports can be overwhelming and time-consuming. This is where automated monitoring comes in. Using DMARC monitoring tools helps convert that complex XML data into clear, actionable insights. These platforms can track your email authentication status over time, visualize trends, and send you real-time alerts when issues arise. For anyone running large-scale email outreach, automated monitoring is essential. It allows you to quickly identify and fix problems before they impact your deliverability, ensuring your email security remains robust without constant manual effort.

Frequently Asked Questions

How does DMARC actually help my email campaigns? Think of DMARC as a way to build trust with inbox providers like Gmail and Outlook. When they see you have a solid DMARC policy, they become more confident that your emails are legitimate, which directly contributes to better inbox placement. It also stops scammers from using your domain, protecting the sender reputation you've worked hard to build from being damaged by phishing attacks you didn't even send.

I'm new to DMARC. What's the absolute first thing I should do? Before you do anything else, create a DMARC record with the policy set to p=none. This puts you in "monitoring mode." It won't block or quarantine any emails, but it will instruct email providers to start sending you reports. These reports show you every single service sending email from your domain, giving you the data you need to fix authentication issues before you start enforcing a stricter policy.

My DMARC record is set up, but my emails are still failing. What's the most likely reason? The most common culprit is a third-party service you use, like a marketing platform, help desk, or CRM. If that service isn't properly authorized in your SPF and DKIM records to send email on your behalf, its messages will fail DMARC checks. You need to review your DMARC reports to identify all your senders and ensure every one is correctly configured in your DNS settings.

Is it risky to set my DMARC policy to 'reject'? I'm worried about blocking my own emails. It can be risky if you jump straight to it without doing your homework first. That's why you should always move in stages. Start with p=none to gather data, then move to p=quarantine to send failing emails to the spam folder. Only after you've monitored the results and are confident that none of your legitimate emails are being flagged should you move to p=reject. This gradual approach is the safest way to protect your domain without disrupting your email flow.

Do I need a separate DMARC policy for my subdomains? While your main domain's policy can influence your subdomains, it's much safer to be explicit. Attackers know that subdomains are often less secure and will target them for spoofing. You can add a specific subdomain policy tag, like sp=reject, to your main DMARC record. This tells receivers to apply a strict policy to all your subdomains, ensuring there are no weak spots for spoofers to exploit.