550 5.7.0: email sending denied
Google refused to send this mail through its servers for your account, and its reply refers you to the SMTP relay error documentation.
- Gmail
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550 5.7.0
- Provider
- Gmail and Google Workspace
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
550 5.7.0 Email sending denied.
What it means
Google gives this reply no explanation beyond a link to its SMTP relay service error messages. The closest match there is 'Mail relay denied': the mail comes from a domain or IP that is not registered for relay in your Workspace account, or the domain with the configured policy could not be identified from HELO and MAIL FROM. That reading is ours, so check the relay setting first. If it is right, the account may be blocked from sending for another reason, which Workspace support can look into.
Common causes
- Relay settings in the Admin console that do not cover the sending IP or domain.
- A HELO name or MAIL FROM address that Google cannot tie to your Workspace account.
- A sending restriction on the account itself.
How to fix it
- 01Check the SMTP relay service setting in the Admin console for the sending IP and the allowed senders.
- 02Make the device send HELO with a fully qualified name and MAIL FROM with an address on your domain.
- 03Look the message up in Email Log Search.
- 04Contact Google Workspace support if the settings are right and sending is still denied.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- Gmail SMTP errors and codes (Google Workspace Admin Help)knowledge.workspace.google.com
- SMTP relay service error messages (Google Workspace Admin Help)knowledge.workspace.google.com
Related codes
- 550 5.7.0Relay denied: sender not registered.Google's SMTP relay refused your mail because it comes from an IP or domain that is not registered in your Google Workspace account's relay settings.
- 550Mailbox unavailable.The receiving server permanently refused the message for this recipient: the mailbox does not exist, cannot be reached, or the server rejected the message by policy.
- 5.7.0Security or policy refusal, unspecified.The message or session was refused for a security or policy reason that the server did not describe more precisely, or chose not to reveal.
5.7.0 at other providers
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