SMTP 211 System Status vs 553 Mailbox Name Invalid
SMTP 211 (System Status) is a 2xx Positive Completion response, while 553 (Mailbox Name Invalid) is a 5xx Permanent Negative response. 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. In contrast, 553 means that the requested action was not taken because the mailbox name is syntactically incorrect. The email address does not conform to the expected format.
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.
Quand vous le voyez
When querying the mail server for its status or capabilities. The server is sharing diagnostic or informational details about itself.
Comment résoudre
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 requested action was not taken because the mailbox name is syntactically incorrect. The email address does not conform to the expected format.
Quand vous le voyez
When the sender or recipient address contains invalid characters, improper formatting, or violates the server's naming conventions.
Comment résoudre
Check the email address format — ensure it follows the standard [email protected] pattern with valid characters. Remove any spaces, special characters, or encoding issues from the address.
Différences clés
211 is a 2xx Positive Completion response, while 553 is a 5xx Permanent Negative response.
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 553: The requested action was not taken because the mailbox name is syntactically incorrect. The email address does not conform to the expected format.
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 553 when when the sender or recipient address contains invalid characters, improper formatting, or violates the server's naming conventions.
Quand utiliser lequel
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 553 (Mailbox Name Invalid): Check the email address format — ensure it follows the standard [email protected] pattern with valid characters. Remove any spaces, special characters, or encoding issues from the address.