Gmail 555 5.5.2
Syntax error
Gmail 555 5.5.2 means: syntax error. It is a permanent failure, so do not retry it unchanged. Gmail could not parse a command. Check MAIL FROM and RCPT TO formatting, including angle brackets.
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
Syntax error. For more information, go to About SMTP error messages and review RFC 5321 specifications.
Reply text
Syntax error, goodbye. For more information, go to About SMTP error messages and review RFC 5321 specifications.
| Who sends it | Gmail and Google Workspace |
|---|---|
| Basic code | 555: MAIL FROM/RCPT TO parameters not recognized or not implemented (RFC) |
| Enhanced code | 5.5.2: Syntax error |
| Permanent or temporary | Permanent (5xx) |
| Verifying the list prevents it | No |
What the sender should do
Gmail could not parse a command. Check MAIL FROM and RCPT TO formatting, including angle brackets.
Would verifying the list have prevented Gmail 555 5.5.2?
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 555 5.5.2 mean?
- Gmail 555 5.5.2 means: syntax error. It is a permanent failure, so do not retry it unchanged. Gmail could not parse a command. Check MAIL FROM and RCPT TO formatting, including angle brackets.
- Should I retry after Gmail 555 5.5.2?
- No. It is a permanent (5xx) failure, so the same message to the same address will fail again. Fix the cause first. Gmail could not parse a command. Check MAIL FROM and RCPT TO formatting, including angle brackets.
- Would verifying my list have prevented Gmail 555 5.5.2?
- 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