SMTP 214 Help Message vs 504 Parameter Not Implemented
SMTP 214 (Help Message) is a 2xx Positive Completion response, while 504 (Parameter Not Implemented) is a 5xx Permanent Negative response. 214 indicates that a help message response containing information about the server's supported commands or a specific command's usage. This is a human-readable reply to the HELP command. In contrast, 504 means that a command parameter is not implemented on this server. The command itself is valid but the specific parameter or extension you used is not supported.
説明
A help message response containing information about the server's supported commands or a specific command's usage. This is a human-readable reply to the HELP command.
このコードが表示される場合
After sending the HELP command to the SMTP server. The response lists available commands or provides usage details for the command you specified.
解決方法
No fix needed — this is a normal informational response. Use the provided help text to understand which commands the server supports.
説明
A command parameter is not implemented on this server. The command itself is valid but the specific parameter or extension you used is not supported.
このコードが表示される場合
When using SMTP extensions or parameters that the server does not support, such as an unsupported AUTH mechanism or an unrecognized MAIL FROM parameter.
解決方法
Check the server's EHLO response for supported extensions and parameters. Use only the mechanisms and parameters listed in the server's capability advertisement.
主な違い
214 is a 2xx Positive Completion response, while 504 is a 5xx Permanent Negative response.
SMTP 214: A help message response containing information about the server's supported commands or a specific command's usage. This is a human-readable reply to the HELP command.
SMTP 504: A command parameter is not implemented on this server. The command itself is valid but the specific parameter or extension you used is not supported.
You encounter 214 when after sending the HELP command to the SMTP server. The response lists available commands or provides usage details for the command you specified.
You encounter 504 when when using SMTP extensions or parameters that the server does not support, such as an unsupported AUTH mechanism or an unrecognized MAIL FROM parameter.
どちらをいつ使うか
For 214 (Help Message): No fix needed — this is a normal informational response. Use the provided help text to understand which commands the server supports. For 504 (Parameter Not Implemented): Check the server's EHLO response for supported extensions and parameters. Use only the mechanisms and parameters listed in the server's capability advertisement.