Attention users! Gmail has officially started rolling out Google email sender policies for 2024, and users are getting the following error:
gmail-smtp-in.l.google.COM: 550-5.7.26 This mail has been blocked because the sender is unauthenticated.
This 550-5.7.26 Gmail unauthentication error means that your domain is missing email authentication implementations. Starting from 1st Feb 2024, Google is gradually enforcing its new email sender guidelines. These guidelines require bulk senders to enable DMARC, SPF, and DKIM for their domains. General senders are not in the clear either, as they are required to implement either SPF or DKIM.
In this article, we will explain how you can quickly deploy these complex-sounding email protocols easily! We will also be providing you with ways to test your current compliance. At the end of this article, you will be able to fix the "gmail-smtp-in.l.google.COM: 550-5.7.26 This mail has been blocked because the sender is unauthenticated" error.
I found PowerDMARC after the Google and Yahoo new email sender requirements were issued. PowerDMARC hooked us up with a monitoring DMARC policy in no time! It helped us slowly (but surely) shift to an enforced policy for better protection.", reported small business owner Rachel R.
Gmail may be blocking your emails if you are not practicing Google's email sender requirements. These requirements are mandatory, and senders who fail to comply can potentially get blocked by Gmail. If some of your non-compliant emails are still getting delivered, you are not in the clear either! Google is rolling out its requirements in a gradual but progressive manner. This means that, in the future, Gmail will surely block all non-compliant emails.
Source: Gmail email sender guidelines
Here are some reasons why Gmail is blocking emails from your domain in 2024:
If you send less than 5000 emails per day, Gmail may be blocking your emails if:
If you send more than 5000 emails per day, Gmail may be blocking your emails if:
Apart from not following the above Gmail email sender best practices, below are more contributing factors:
Gmail can block outgoing emails containing spam content. Poorly written and grammatically incorrect emails can be detected as spammy. Moreover, if you include attachments in your emails that contain viruses, Gmail can block the email.
Gmail will also consider emails containing questionable content as harmful. This includes emails curated to scam people, sell something illegal, or promote dangerous content.
Your domain reputation is very important. If you have a poor sender reputation, Gmail may block your future emails. This doesn't necessarily mean that all your emails are bad. This is merely an indication that your domain has been reported as spam by various sources in the past. This may have led to your sender reputation score going down.
If your domain is on an IP blocklist, Gmail may block your outgoing emails. You can sign up for our reputation monitoring service to review blocklisted domains. Getting whitelisted will automatically improve your Gmail email delivery rates.
Gmail places a high focus on message relevance. In Google's 2024 email sender guidelines, they have asked senders to only send emails that will be of value to users. This means that you should not send email ads for women's perfume to a male receiver. This defies user interest, as the email may not be of value to him. Instead, send emails keeping user interest in mind.
If Gmail is blocking your emails, you may receive the following error message:
In the example shown above, Gmail has blocked the sender's email because it is unauthenticated. In the message, Gmail mentions neither SPF nor DKIM has passed for the email - leading to rejection. This might be because:
PowerDMARC customers can easily check if Gmail is blocking emails on the DMARC report analyzer dashboard. Our human-readable reports provide visibility on your mail flows, so you can detect email delivery issues quickly!
After you are sure that Gmail is blocking your emails, it's time to fix the error. Let's find out how:
To fix 550 5.7.26 Gmail email delivery issue and stop Gmail from blocking your emails, follow these steps:
To fix "Gmail email blocked because the sender is unauthenticated" error, you must set up SPF. SPF helps you authenticate your sending sources to establish them as trusted senders. You can implement SPF with a DNS TXT record created using an SPF generator tool. Once created, access your DNS management console to publish the SPF record.
Setting up DKIM for your domain is another step towards compliance. DKIM is an internet protocol that helps you authenticate message content. If an attacker tries to change your email's content, DKIM can prevent it. To implement DKIM, you need to publish a DNS record created using a DKIM generator tool. This record must be published on your Domain Name System.
Whether you send bulk messages or not, we recommend all mail senders to deploy DMARC. Domain-based Message Authentication, Reporting, and Conformance can prevent many email-based cyberattacks. Gmail recommends DMARC for its anti-phishing benefits, ability to improve sender credibility, and establish trust. To deploy DMARC, you need to publish your DMARC DNS record created using a DMARC generator tool.
It's not easy to manually implement SPF, DKIM, and DMARC. To set up and manage all your email authentication implementations in one place, you can try our DMARC analyzer. This tool truly does it all!
"I started using PowerDMARC after Gmail's new requirements affected my marketing emails. I was pleasantly surprised at how easy it was to use! Within a matter of minutes, my emails were meeting all of Gmail's email authentication requirements.", said business owner Rachel R.
Your marketing, sales, and transactional emails should be easy to unsubscribe. You can include a clear unsubscribe link on top of your emails that works with a single click. This will help receivers filter out emails they don't want, instead of blocking them.
Google is constantly updating and improving their email sending best practices. Every email marketer and domain owner must closely monitor these practices to stay compliant. Falling behind on the latest updates can reflect badly on your next email marketing campaign.
PowerDMARC can help you easily fix the Gmail "550 5.7.26 This Mail is Unauthenticated" error. What's even better? You don't need any technical help, or weeks of your time for this! PowerDMARC's Google and Yahoo Compliance Program is designed to make compliance effortless for domain owners. We help you:
PowerDMARC supports multiple tenants and 11 different language versions. The platform is a no-brainer to use for even those who know nothing about email authentication. The best part? Whether you are an enterprise owner or a small business, our services won't dig a hole in your pocket! So sign up today to get your free DMARC trial.
It's a wrap! We hope this article helped you resolve the Gmail "550 5.7.26 This Mail is Unauthenticated" error. Feel free to recommend our post to anyone facing Gmail email delivery issues in 2024. For further assistance, contact us to talk to a Gmail email security compliance expert!