550 5.7.26 Gmail bounce: SPF hard fail
What 550 5.7.26 means
The envelope sender's SPF record ends in -all (hard fail), and the sending IP is not listed, so Gmail rejects the message.
Message text
The (E)MAIL FROM domain [domain-name] has an SPF record with a hard fail policy (-all) but it fails to pass SPF checks…
This is an excerpt: the provider's documentation shortens the message. Full text: provider documentation
Common causes of 550 5.7.26
- Sending IP or service is not in the SPF record
- SPF record ends in -all while some legitimate senders are missing
How to fix 550 5.7.26
- Run SPF checker and add the sending service's include or ip4 mechanism.
- Make sure every service that sends for the domain is listed before relying on -all.
Check your domain
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How to read 550 5.7.26
The first part, 550, is the SMTP reply code. Requested action not taken, mailbox unavailable: the mailbox does not exist, is not allowed, or the message was refused for policy reasons. Replies that start with 4 are temporary and replies that start with 5 are permanent (RFC 5321 §4.2.1).
The second part, 5.7.26, is an enhanced status code (RFC 3463 §2) written class.subject.detail. Class 5 is a Permanent failure (5xx): the command was rejected and the sender should not repeat it unchanged (RFC 5321 §4.2.1; RFC 3463 §2).. Subject 7 is security or policy: authentication, authorization or policy refused the message. The detail number refines the subject, and providers may define details of their own, which is why one code can read differently at Gmail, Microsoft and Yahoo.
Do not keep resending the same message: a permanent failure repeats until the cause is fixed. Correct the cause, then send a new message.
Official source: knowledge.workspace.google.com. Last verified 2026-10-20.
Related guides
- DMARC fails even though SPF and DKIM pass: fixing alignment
- How to create an SPF record (syntax and examples)
- How DKIM works and how to publish a DKIM record
Related codes
- 5.7.26 SMTP: authentication failed
- 550 5.7.26 Gmail: blocked by dmarc policy
- 550 5.7.26 Gmail: no spf or dkim pass
- 5.7.0 SMTP: security status
- 5.7.1 SMTP: delivery not authorized
- 5.7.23 SMTP: SPF validation failed
FAQ
What does 550 5.7.26 mean?
The envelope sender's SPF record ends in -all (hard fail), and the sending IP is not listed, so Gmail rejects the message. This is a permanent failure.
How do I fix 550 5.7.26?
Run SPF checker and add the sending service's include or ip4 mechanism. Make sure every service that sends for the domain is listed before relying on -all.
Is 550 5.7.26 permanent, and should I retry?
550 5.7.26 is a permanent failure, so retrying the same message will fail again. Fix the cause first, then send a new message.