SMTP 211 System Status vs 235 Authentication Successful
Both SMTP 211 (System Status) and 235 (Authentication Successful) belong to the 2xx Positive Completion category. 211 indicates that a system status reply providing information about the mail server's current state. This is typically sent in response to a HELP or system inquiry command. Meanwhile, 235 means that the client has been successfully authenticated using the AUTH command. The server will now accept mail commands from this authenticated session.
Description
A system status reply providing information about the mail server's current state. This is typically sent in response to a HELP or system inquiry command.
When You See It
When querying the mail server for its status or capabilities. The server is sharing diagnostic or informational details about itself.
How to Fix
No fix needed — this is an informational response. If the status indicates a problem, review the server's configuration or contact the mail administrator.
Description
The client has been successfully authenticated using the AUTH command. The server will now accept mail commands from this authenticated session.
When You See It
After submitting valid credentials via the AUTH command (LOGIN, PLAIN, or other SASL mechanism). The server has verified your identity and you can now send mail.
How to Fix
No fix needed — authentication succeeded. If you expected this but received a different code, double-check your username, password, and the authentication mechanism.
Key Differences
SMTP 211: A system status reply providing information about the mail server's current state. This is typically sent in response to a HELP or system inquiry command.
SMTP 235: The client has been successfully authenticated using the AUTH command. The server will now accept mail commands from this authenticated session.
You encounter 211 when when querying the mail server for its status or capabilities. The server is sharing diagnostic or informational details about itself.
You encounter 235 when after submitting valid credentials via the AUTH command (LOGIN, PLAIN, or other SASL mechanism). The server has verified your identity and you can now send mail.
When to Use Which
For 211 (System Status): No fix needed — this is an informational response. If the status indicates a problem, review the server's configuration or contact the mail administrator. For 235 (Authentication Successful): No fix needed — authentication succeeded. If you expected this but received a different code, double-check your username, password, and the authentication mechanism.