SMTP 214 Help Message vs 521 Host Does Not Accept Mail
SMTP 214 (Help Message) is a 2xx Positive Completion response, while 521 (Host Does Not Accept Mail) 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, 521 means that the host does not accept mail at all. This indicates the server exists but is explicitly configured to reject all incoming email messages.
Описание
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.
Когда вы это видите
After sending the HELP command to the SMTP server. The response lists available commands or provides usage details for the command you specified.
Как исправить
No fix needed — this is a normal informational response. Use the provided help text to understand which commands the server supports.
Описание
The host does not accept mail at all. This indicates the server exists but is explicitly configured to reject all incoming email messages.
Когда вы это видите
When connecting to a server that has been intentionally configured to refuse all email, such as a domain that only sends but never receives mail.
Как исправить
Verify you are connecting to the correct mail server by checking the domain's MX records. If the domain truly does not accept mail, contact the recipient through an alternative channel.
Ключевые различия
214 is a 2xx Positive Completion response, while 521 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 521: The host does not accept mail at all. This indicates the server exists but is explicitly configured to reject all incoming email messages.
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 521 when when connecting to a server that has been intentionally configured to refuse all email, such as a domain that only sends but never receives mail.
Когда что использовать
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 521 (Host Does Not Accept Mail): Verify you are connecting to the correct mail server by checking the domain's MX records. If the domain truly does not accept mail, contact the recipient through an alternative channel.