Gmail's 550 5.7.26 error: what it means and how to fix it
Gmail bounced your email because it couldn’t confirm the email really came from you. Gmail requires every sender to pass at least one of its identity checks, and it rejects email that fails when your domain’s settings say to. The fix is in your domain’s settings, usually for one tool that isn’t approved yet.
Check your own email first. Free, about 90 seconds. You get a grade and a plain-English list of what's working and what isn't.
The message you’re seeing
Google uses 550 5.7.26 for three slightly different problems. Find the one that matches your bounce.
This email has been blocked because the sender is unauthenticated. Gmail requires all senders to authenticate with either SPF or DKIM.
The tool that sent this email isn’t approved on your domain at all. Most often it’s a newer tool someone started using.
The (E)MAIL FROM domain [your domain] has an SPF record with a hard fail policy (-all) but it fails to pass SPF checks…
Your approved senders list is set to strict, and the server that sent this email isn’t on it.
Unauthenticated email from [your domain] is not accepted due to domain’s DMARC policy.
Your protection setting is turned up to block failures, and this email failed. The protection is doing its job, but on your own email.
What to do
- Run the free check below to see which settings are missing.
- Work out which tool sent the bounced email. The bounce is a reply to that email, so look at what you sent and where you sent it from.
- Approve that tool on your domain using its “verify your domain” setting.
- If your protection setting is set to block, ask your web person to turn it back to watch-only until every tool passes. That stops your own email bouncing while you fix things.
What this guide can’t do for you
It covers the common causes. It can’t tell you which of your tools is the one that’s failing, or give you the exact settings for your business and the company that manages your domain. That’s what the Email Fix does. We check every tool that sends email for you and give you steps written for your setup. If we can't find what's wrong with your email settings, you get your $299 back. The guarantee covers your email settings. No settings can fix email sent to people who didn't ask for it, like bought lists or mass emails.
See what's wrong with your email, free
Type in your business's web address (the part after the @ in your email). You'll get a plain-English answer: what's working, what isn't, and what to do next.
Common questions
Why did this start now?
Since February 2024, Gmail has required every sender to pass at least one identity check. Email that used to get through without them now bounces.
Only some of my emails bounce. Why?
Each tool you send from is checked separately. Your mailbox might pass while your invoicing or newsletter tool fails.
Is 421 4.7.26 the same thing?
It's the temporary version. Gmail is slowing or deferring your email for the same reason, and may start rejecting it if nothing changes.
For your IT person or web developer
You can forward this page as it is. Everything below is written so someone who doesn't work with email settings every day can follow it.
Google's SMTP error reference lists three 550 5.7.26 variants:
“Sender is unauthenticated… SPF or DKIM”
Neither SPF nor DKIM passed. Add the sending service to SPF and enable DKIM signing for the domain in that service.
“SPF record with a hard fail policy (-all)”
The connecting IP isn't in the envelope domain's SPF record, which ends in -all. Add the missing service's include:, or use ~all while you audit senders.
“Not accepted due to domain's DMARC policy”
DMARC failed under p=quarantine or p=reject. Get the sender aligned (DKIM d= or SPF envelope domain matching the From domain), or temporarily step the policy back to p=none.
Related: 421 4.7.26 is the rate-limited version; 550 5.7.40 means a bulk sender has no DMARC record. Step-by-step DNS changes are in the business email going to spam guide.
Check it worked
DNS changes usually show within an hour, though some hosts take up to a day or two. Then send a test message to a personal Gmail address, open it, click the three dots at the top right of the message and choose Show original. You want to see SPF: PASS, DKIM: PASS and DMARC: PASS. You can also run the free check at senderfix.com again.
Related guides
Written by the SenderFix team. Last updated .