Gmail 550 5.7.0
SMTP relay denied or sending denied
Gmail 550 5.7.0 means: sMTP relay denied or sending denied. It is a permanent failure, so do not retry it unchanged. Gmail's SMTP relay refused the message: the sending IP or domain is not registered in the Workspace account, or the account is suspended for abuse. Check relay settings in the Admin console.
Gmail’s exact wording
Quoted from Google Workspace Admin Help: Gmail SMTP errors and codes, checked 2026-11-05. Placeholders are Gmail’s own.
Reply text
Email relay denied ip-address. Invalid credentials for relay for one of the domains in: domain-name (as obtained from HELO and (E)MAIL FROM). Email is being sent from a domain or IP address which isn't registered in your Workspace account. Please login to your Workspace account and verify that your sending device IP address has been registered within the Workspace SMTP Relay Settings. For more information, go to SMTP relay service error messages.
Reply text
Email relay denied ip-address. The sending email account has been temporarily suspended due to abuse. For more information, go to SMTP relay spam policy in Gmail.
Reply text
Email sending denied. For more information, go to SMTP relay service error messages.
| Who sends it | Gmail and Google Workspace |
|---|---|
| Basic code | 550: Requested action not taken: mailbox unavailable (e.g., mailbox not found, no access, or command rejected for policy reasons) (RFC) |
| Enhanced code | 5.7.0: Other or undefined security status |
| Permanent or temporary | Permanent (5xx) |
| Verifying the list prevents it | No |
In practice
These replies come from Google Workspace's SMTP relay service, not from Gmail's inbound servers. The relay refuses mail when the sending IP or domain is not registered in the Workspace account, when the account has been suspended for abuse, or when sending is denied. The fix is in the Google Admin console relay settings: allowed IPs, allowed senders and authentication requirements.
What the sender should do
Gmail's SMTP relay refused the message: the sending IP or domain is not registered in the Workspace account, or the account is suspended for abuse. Check relay settings in the Admin console.
Would verifying the list have prevented Gmail 550 5.7.0?
No
This reply is about your sending setup, the message or the receiving system, not about whether the address exists, so verifying the list will not prevent it.
Common questions
- What does Gmail 550 5.7.0 mean?
- Gmail 550 5.7.0 means: sMTP relay denied or sending denied. It is a permanent failure, so do not retry it unchanged. Gmail's SMTP relay refused the message: the sending IP or domain is not registered in the Workspace account, or the account is suspended for abuse. Check relay settings in the Admin console.
- Should I retry after Gmail 550 5.7.0?
- No. It is a permanent (5xx) failure, so the same message to the same address will fail again. Fix the cause first. Gmail's SMTP relay refused the message: the sending IP or domain is not registered in the Workspace account, or the account is suspended for abuse. Check relay settings in the Admin console.
- Would verifying my list have prevented Gmail 550 5.7.0?
- No. This reply is about your sending setup, the message or the receiving system, not about whether the address exists, so verifying the list will not prevent it.
Sources
- Google Workspace Admin Help: Gmail SMTP errors and codes (checked 2026-11-05)
- IANA: SMTP Enhanced Status Codes registry (checked 2026-11-05)
- RFC 5321: Simple Mail Transfer Protocol, section 4.2.3 (reply codes) (checked 2026-11-05)
Registry and provider wording is quoted exactly; guidance is written by the SimpleVerifier Team.
SimpleVerifier Team · Last checked against the sources 2026-11-05