How to Tackle Common Email Authentication Issues and Improve Email Deliverability

Struggling with email authentication issues? Learn how to fix common problems with SPF, DKIM, and DMARC to protect your sender reputation and improve email deliverability. Discover simple methods and tools to ensure your emails land in inboxes—not spam folders.

Every time you send an email, it’s like giving someone a letter. But before it gets to the person you want to reach, the “mail service” (your email provider) checks to see if you’re trustworthy. 

Email authentication is how you prove you’re not a scammer or spammer. Think of it as showing ID at the door before you gain access to an event.

If your emails aren’t properly authenticated, they are highly likely to end up in the spam folder—or worse, never get delivered at all. So how can you prevent that and connect with your customers instead?

In no time at all, we’ll break down common email authentication issues and show you how to solve them.

What causes email authentication issues?

Email authentication issues often arise from small mistakes or misunderstandings about how protocols like SPF, DKIM, and DMARC work. These problems can reduce email deliverability and harm your sender reputation. 

Here are some of the most common causes and why they matter:

• Lack of knowledge about SPF, DKIM, and DMARC protocols
  Many businesses don’t fully understand what these protocols do or how to set them up. Without a solid grasp, they may skip crucial steps or implement incomplete solutions, leaving emails vulnerable to being flagged as spam or rejected.
• Missing or outdated DNS records
  Email authentication relies on specific DNS (Domain Name System) records to verify your identity. If these records are missing or aren’t updated when you make changes (like switching email providers), it can lead to failed authentication checks.
• Overly strict or overly lenient DMARC policies
  Setting your DMARC policy to reject or quarantine emails without first monitoring and fine-tuning can block legitimate emails. On the other hand, a policy that’s too lenient, like “none,” offers little protection against spoofing or phishing. 
• Misaligned domain settings across email platforms
  If you send emails from multiple platforms (e.g., marketing tools, CRM tools, or transactional email services), the domain alignment may not match. This mismatch can cause emails to fail SPF or DKIM checks. Double-checking your SPF configuration and DKIM setup is key.
• Complex SPF records with too many servers listed
  SPF records have a limit on how many lookups they can perform. If your SPF record includes too many servers or unnecessary entries, it might exceed the limit, causing authentication to fail.

Related: Try this free DMARC checker to see if there are any errors in your DMARC records

By addressing these common email authentication issues, you can build trust with inbox providers, improve your email deliverability, and ensure that your messages reach your customers.

What is email authentication?

Email authentication is the process of verifying that an email message comes from the sender it claims to represent. It uses specific protocols to confirm the sender’s identity and protect against spam, phishing, and email spoofing.

Let’s take a closer look at email authentication protocols and how they work to ensure your messages are legitimate and trustworthy.

Email authentication protocols: what are SPF, DKIM, and DMARC? 

Email authentication is like a digital trust test for your emails. It ensures that your messages are actually coming from you and not someone pretending to be you. 

Three major tools help email systems figure out if you’re legit: SPF, DKIM, and DMARC. Here’s what they do:

• SPF (Sender Policy Framework): This is like a guest list. It tells email systems which servers are allowed to send emails on your behalf. If the sender isn’t on the list, the email might get flagged.
• DKIM (DomainKeys Identified Mail): Think of this as a wax seal on your letter. It adds a digital signature to your emails so recipients know they haven’t been tampered with on the way.
• DMARC (Domain-based Message Authentication, Reporting, and Conformance): It uses SPF and DKIM to decide whether to let your email in, block it, or send it to spam. DMARC also gives you feedback about any email authentication failures.

These protocols work together to keep spam and phishing emails out of inboxes—but only if they’re set up right.

Common email authentication issues and their impact on email deliverability

Even if you’re familiar with SPF, DKIM, and DMARC and have taken steps to adopt them, mistakes can easily creep in. 

Here are some of the most common problems:

• SPF records are too long or incomplete: If your SPF record has too many servers listed or isn’t specific enough, emails might fail authentication.
• Missing or incorrect DKIM setup: Forgetting to add a DKIM record or using an outdated key can make your emails look suspicious.
• No DMARC policy: Without a DMARC policy, you miss out on key insights into why your emails might be failing—and your messages are more vulnerable to spoofing.
• Overly strict policies: On the flip side, policies that are too aggressive can block legitimate emails, causing frustration for your recipients and harm to your sender reputation.

These email authentication issues affect whether your email gets delivered. Also, they can harm your reputation as a sender and make it harder for your future messages to reach inboxes.

Why major email providers require email authentication

If you’re planning to implement or improve your email authentication, you’re on the right path to building trust with email service providers. 

In 2024, major providers like Google, Yahoo, and Microsoft made it a rule for mass senders to authenticate their emails and thus prove legitimacy. 

“Starting in 2024, we’ll require bulk senders to authenticate their emails, allow for easy unsubscription and stay under a reported spam threshold,” Google’s Group Product Manager Neil Kumaran wrote in a blog post.

“We’ve focused on a crucial aspect of email security: the validation that a sender is who they claim to be,” Kumaran explained.

This validation mitigates the risk of spoofing and spam as domains are more secure.

Yahoo’s Senior Director of Product Management Marcel Becker reiterated:

“A pivotal aspect of addressing these concerns involves sender validation, leveraging email authentication standards to guarantee the verification of the email sender’s identity.”

Related: See what Yahoo’s Marcel Becker told us about Yahoo email bounces.

How regional differences impact email authentication 

Email authentication practices vary around the world. Some regions have stricter standards, while others lag in adoption.

• North America and Europe: Businesses here often lead the way in using DMARC authentication and other protocols. However, they can still struggle with overly complex setups.
• Asia and Africa: Adoption is growing but remains uneven, particularly among smaller businesses. Limited awareness often leads to basic email authentication issues, like missing SPF or DKIM records.
• Latin America: Issues often arise from using outdated email platforms that don’t fully support modern authentication protocols.

The solution? Start with education. 

Understanding the basics of email authentication and using the right tools can help your business meet global standards. It helps you improve email deliverability and forge better relationships with your customers.

How to fix email authentication issues: tools and strategies

Fixing email authentication issues might seem technical, but it’s easier than you think with the right approach. By identifying and addressing misconfigurations, you can keep your domain safe and boost your email deliverability.

Here’s how to troubleshoot and resolve common email authentication challenges:

Use online checkers

Free online tools are a quick and easy way to pinpoint problems with your SPF, DKIM, or DMARC setup. They can scan your domain’s DNS records, highlight misconfigurations, and give you recommendations. 

Some tools also simulate email sending to show how different providers view your email authentication settings. This helps you address issues before they affect your deliverability.

Simplify your SPF record

SPF records have a limit of 10 DNS lookups, and exceeding this can cause emails to fail authentication. If your record is too long, remove unnecessary servers or consolidate multiple entries using services like subdomains. 

Some tools can optimize your SPF record by restructuring it to stay within the limits while maintaining functionality.

Regularly update DKIM keys

DKIM keys add a layer of security, but they can become outdated if left unchanged for too long. Regular updates ensure that your keys remain strong against potential threats. Make it a habit to review your DKIM setup every year. Also, rotate your keys to stay on top of your email security.

Start with a relaxed DMARC policy

Jumping straight into a strict DMARC policy (like rejecting all unauthenticated emails) can cause problems, especially if your SPF or DKIM setup isn’t perfect yet. 

Start with a “monitor-only” policy, which allows you to gather data on email failures without impacting deliverability. Use the reports to refine your setup before gradually tightening the policy.

If you need help setting up your DMARC policy, our team is available 24/7 to assist you.

Monitor deliverability

Keeping an eye on your analytics helps you understand how your emails perform over time. Track metrics like inbox placement rates and bounce rates to identify trends or sudden drops that could indicate email authentication problems. 

Many tools offer dashboards to help visualize your deliverability performance. This makes it easier for you to adjust your settings and maintain a strong sender reputation.

How ZeroBounce helps with email authentication and deliverability

If all of this feels overwhelming, don’t worry—tools like ZeroBounce make email authentication easy. ZeroBounce offers:

• SPF, DKIM, and DMARC setup assistance: Get step-by-step help to configure your email settings properly.
• Email deliverability testing: Monitor how well your emails perform and catch issues before they escalate.
• Sender reputation insights: Find out email providers perceive your domain and get tips to improve your score.

By fixing email authentication issues and maintaining a strong sender reputation, ZeroBounce ensures your emails land where they belong: in your recipients’ inboxes.

When dealing with email authentication, always keep this in mind

Email authentication doesn’t have to be a headache. By understanding the basics of SPF, DKIM, and DMARC and using the right tools to implement them, you can boost your email deliverability and protect your sender reputation.

Start tackling those email authentication issues today. Your inbox placement depends on it.Just remember that there’s always someone to help you. That’s us. It doesn’t matter whether you’re our customer or not—reach out and we’ll help you secure your domain.