SMTP 354 Start Mail Input vs 451 Local Error
SMTP 354 (Start Mail Input) is a 3xx Positive Intermediate response, while 451 (Local Error) is a 4xx Transient Negative response. 354 indicates 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). In contrast, 451 means that the requested action was aborted due to a local error in processing. The server encountered an internal issue that prevented it from completing the command.
Descrição
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).
Quando você o vê
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.
Como corrigir
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.
Descrição
The requested action was aborted due to a local error in processing. The server encountered an internal issue that prevented it from completing the command.
Quando você o vê
When the receiving server hits an internal error such as a database failure, DNS lookup timeout, or anti-spam filter processing error.
Como corrigir
Retry the message later. If you control the server, check its logs for the specific error — common causes include DNS resolution failures, disk I/O errors, or database connectivity issues.
Diferenças principais
354 is a 3xx Positive Intermediate response, while 451 is a 4xx Transient Negative response.
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).
SMTP 451: The requested action was aborted due to a local error in processing. The server encountered an internal issue that prevented it from completing the command.
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.
You encounter 451 when when the receiving server hits an internal error such as a database failure, DNS lookup timeout, or anti-spam filter processing error.
Quando usar qual
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. For 451 (Local Error): Retry the message later. If you control the server, check its logs for the specific error — common causes include DNS resolution failures, disk I/O errors, or database connectivity issues.