Gmail / Google - This message does not have authentication information or fails to pass authentication checks

What is the problem?

Gmail / Google are rejecting your message because it does not pass sender authentication checks.

The error message that they return is:

550-5.7.26 This message does not have authentication information or fails to pass authentication checks. To best protect our users from spam the message has been blocked. Please visit https://support.google.com/mail/answer/81126#authentication for more information.

What are sender authentication checks?

Sender authentication is a number of technologies that help domain name owners protect their domain names from being used by others to send spam or spoofed emails (phishing) from their domain name.

The technologies are:

Why is this happening now?

Google and other mailbox providers have strengthened their sender-authentication requirements over time. Missing, invalid or unaligned authentication can cause messages to be rejected, filtered or displayed with a warning.

How do I resolve this and send emails to Gmail users?

The most common reasons for this error include:

  • The existing SPF record on your domain name does not include the AuthSMTP.com network
  • You do not have an SPF record setup on your domain name
  • The existing SPF record is invalid
  • AuthSMTP DKIM has not been configured or is failing verification
  • The domain has no valid DMARC record, or neither SPF nor DKIM aligns with the visible From domain

Check all three authentication methods. Before a customer-owned domain can be authorised with AuthSMTP, it must have a valid SPF record that includes the AuthSMTP network and every other legitimate sender, a valid DMARC record, and verified AuthSMTP DKIM signing. p=none is acceptable as a starting DMARC monitoring policy, with a planned progression to p=quarantine and then p=reject after checking reports and alignment.

If you are already familiar with SPF records and you just need to add AuthSMTP to your SPF - please use:

include:authsmtp.com

If you don't have an existing SPF record or if you need more information, please see:

What is SPF? (Sender Policy Framework)

If you have any issues with configuring your SPF record or email delivery, please login to the Control Panel and raise a ticket.