550 5.7.26: Gmail: unauthenticated email is not accepted
Gmail rejected the message because it failed or lacks SPF, DKIM or DMARC authentication.
Rejected by policy or reputation
What 550 5.7.26 means
Google's bounce documentation lists 5.7.26 for mail that fails authentication, including senders who do not meet Gmail's requirements for authenticating mail.
Common causes
- No SPF or DKIM record for the sending domain
- SPF or DKIM that fails to align with the From domain
- A DMARC policy of reject with failing alignment
- Sending through a service that is not authorised in your SPF
How to fix it
- Publish SPF and DKIM for every service that sends your mail
- Add a DMARC record and make sure at least one method aligns
- Test with an SPF, DKIM and DMARC checker
What to do with the address
Not an address problem. Fix your authentication.
Check an address now with the free email checker, or look at a domain's mail setup with the email domain checker, MX lookup and SPF checker.
Related error codes
Frequently asked questions
- What does 550 5.7.26 mean?
- Gmail rejected the message because it failed or lacks SPF, DKIM or DMARC authentication. Google's bounce documentation lists 5.7.26 for mail that fails authentication, including senders who do not meet Gmail's requirements for authenticating mail.
- Is 550 5.7.26 a hard bounce or a soft bounce?
- Rejected by policy or reputation. It is usually about the sender, not the recipient.
- What should I do with the address after 550 5.7.26?
- Not an address problem. Fix your authentication.