Gmail error fix
Gmail 550 5.7.26: why your email bounced and how to fix it
This error means Gmail couldn't confirm the email really came from your domain, so it refused it. The fix is almost always in your DNS records.
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The three versions of the error
Gmail uses 550 5.7.26 for three different problems. Match the text in your bounce to the one below.
- “The sender is unauthenticated. Gmail requires all senders to authenticate with either SPF or DKIM.” Neither check passed. The service that sent this email isn't set up for your domain.
- “The (E)MAIL FROM domain has an SPF record with a hard fail policy (-all) but it fails to pass SPF checks.” Your SPF record ends in -all and doesn't include the service that sent this message.
- “Unauthenticated email is not accepted due to domain's DMARC policy.” The domain's DMARC policy says to reject failing mail, and this message failed. If it's your domain, one of your real senders isn't set up.
Wording from Google's Gmail SMTP error reference (support.google.com/a/answer/3726730).
How to fix it
01
Find the sender
Which service sent the email that bounced? Google Workspace, Microsoft 365, your CRM, a cold email tool, a website form or invoicing.
02
Run the free check
The box above shows your SPF, DKIM and DMARC records and what's missing.
03
Add the service to SPF
Merge it into your one SPF record. Don't add a second SPF record.
04
Turn on DKIM in that service
Publish the record it gives you and switch signing on.
05
Keep DMARC strict
If your policy is quarantine or reject, fix the sender rather than loosening DMARC, so fakes stay blocked.
06
Test
Send to a Gmail address, open the message, choose Show original and confirm SPF, DKIM and DMARC say PASS.
Related Gmail codes
- 550 5.7.27: SPF didn't pass. Gmail requires SPF from bulk senders.
- 550 5.7.30: DKIM didn't pass. Gmail requires DKIM from bulk senders.
- 550 5.7.40: no DMARC record, or no policy in it. Required for bulk senders.
- 421 4.7.26: the temporary version. Gmail is rate limiting unauthenticated mail instead of refusing it.
Questions
- Is 550 5.7.26 a problem on the recipient's side?
- No. It's about the sender's domain. The fix is on your side, in your DNS records or your sending service.
- I only send a few emails a day. Why am I getting this?
- Gmail requires SPF or DKIM from every sender, not just bulk senders.
- How soon will Gmail accept my email after the fix?
- New messages are checked against your records as soon as DNS updates. Confirm the free check passes, then resend.
- Can I fix this without touching DNS?
- Rarely. For email from your own domain, the records that prove it's you live in your DNS.
Want it done for you?
We fix your email health for a fixed price, from $249.
We find every service that sends email as you, fix SPF and DKIM for each one, and move DMARC to blocking fakes once your real mail passes. You keep every account.