SMTP 252 Cannot Verify User vs 354 Start Mail Input
SMTP 252 (Cannot Verify User) is a 2xx Positive Completion response, while 354 (Start Mail Input) is a 3xx Positive Intermediate response. 252 indicates that the server cannot verify the user but will accept the message and attempt delivery. This is often returned in response to VRFY when the server intentionally hides user information. In contrast, 354 means that the server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF).
説明
The server cannot verify the user but will accept the message and attempt delivery. This is often returned in response to VRFY when the server intentionally hides user information.
このコードが表示される場合
When using the VRFY command to check if a recipient exists. The server refuses to confirm or deny the address, typically as a spam-prevention measure.
解決方法
No fix needed — the server will still attempt delivery. If you need to verify addresses, contact the mail administrator or rely on bounce-back messages instead.
説明
The server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF).
このコードが表示される場合
After sending the DATA command. The server is now waiting for you to type or stream the email message, ending with a dot on its own line.
解決方法
Send your message content followed by a line with just a period (.) to signal the end. If you get an error after this, check that your message does not contain a bare period on a line by itself within the body.
主な違い
252 is a 2xx Positive Completion response, while 354 is a 3xx Positive Intermediate response.
SMTP 252: The server cannot verify the user but will accept the message and attempt delivery. This is often returned in response to VRFY when the server intentionally hides user information.
SMTP 354: The server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF).
You encounter 252 when when using the VRFY command to check if a recipient exists. The server refuses to confirm or deny the address, typically as a spam-prevention measure.
You encounter 354 when after sending the DATA command. The server is now waiting for you to type or stream the email message, ending with a dot on its own line.
どちらをいつ使うか
For 252 (Cannot Verify User): No fix needed — the server will still attempt delivery. If you need to verify addresses, contact the mail administrator or rely on bounce-back messages instead. For 354 (Start Mail Input): Send your message content followed by a line with just a period (.) to signal the end. If you get an error after this, check that your message does not contain a bare period on a line by itself within the body.