Permanent failure — do not retry
SMTP 530 5.7.0
must issue STARTTLS or authenticate first
SMTP 530 5.7.0 means the server needs your client to encrypt the connection with STARTTLS, or to authenticate, before it will accept mail. Google returns "Must issue a STARTTLS command first." and "Authentication required." with this code. It is a client setting, not a recipient problem.
How it appears
530 5.7.0 Must issue a STARTTLS command first.
530 5.7.0 Authentication required.
What causes it
- The client connected on port 587 but never upgraded the connection with STARTTLS.
- SMTP authentication is turned off in the client or app.
- An old device or library does not support STARTTLS.
How to fix it
In order — try the first one first.
- Turn on STARTTLS (port 587) or SSL/TLS (port 465) in the client settings.
- Turn on SMTP authentication with the account's credentials, or an app password if two-factor is on.
- Update or replace devices and libraries that cannot do TLS.
Common questions
- What does SMTP 530 5.7.0 mean?
- SMTP 530 5.7.0 means the server needs your client to encrypt the connection with STARTTLS, or to authenticate, before it will accept mail. Google returns "Must issue a STARTTLS command first." and "Authentication required." with this code. It is a client setting, not a recipient problem.
- Should I retry a 530 5.7.0 error?
- No. 530 is a permanent failure, so the message will never be delivered no matter how many times you try. Remove the address — repeated sends to permanent failures are one of the main signals mailbox providers use to throttle a sender.
- How do I fix SMTP 530 5.7.0?
- Turn on STARTTLS (port 587) or SSL/TLS (port 465) in the client settings.
Other 530 replies
Last reviewed 2026-09-11