Gmail 530 5.7.0
Authentication required or STARTTLS first
Gmail 530 5.7.0 means: authentication required or STARTTLS first. It is a permanent failure, so do not retry it unchanged. Gmail requires the client to start TLS and authenticate before sending. Enable TLS and sign in with the account's credentials.
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
Authentication required. For more information, go to Can't sign in to your Google Account.
Reply text
Must issue a STARTTLS command first. For more information, go to About SMTP error messages and review RFC 3207 specifications.
| Who sends it | Gmail and Google Workspace |
|---|---|
| Basic code | 530: Authentication required (RFC) |
| Enhanced code | 5.7.0: Other or undefined security status |
| Permanent or temporary | Permanent (5xx) |
| Verifying the list prevents it | No |
In practice
Gmail's submission servers need two things before they accept mail: an encrypted connection and authentication. Must issue a STARTTLS command first means the client tried to send in plain text. Authentication required means it never logged in. For smtp.gmail.com use port 587 with STARTTLS or 465 with TLS, and an app password or OAuth.
What the sender should do
Gmail requires the client to start TLS and authenticate before sending. Enable TLS and sign in with the account's credentials.
Would verifying the list have prevented Gmail 530 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 530 5.7.0 mean?
- Gmail 530 5.7.0 means: authentication required or STARTTLS first. It is a permanent failure, so do not retry it unchanged. Gmail requires the client to start TLS and authenticate before sending. Enable TLS and sign in with the account's credentials.
- Should I retry after Gmail 530 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 requires the client to start TLS and authenticate before sending. Enable TLS and sign in with the account's credentials.
- Would verifying my list have prevented Gmail 530 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.
The same code elsewhere
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 4954: SMTP Service Extension for Authentication (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