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.
Description
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.
When You See It
After sending the HELP command to the SMTP server. The response lists available commands or provides usage details for the command you specified.
How to Fix
No fix needed — this is a normal informational response. Use the provided help text to understand which commands the server supports.
Description
The host does not accept mail at all. This indicates the server exists but is explicitly configured to reject all incoming email messages.
When You See It
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.
How to Fix
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.
Key Differences
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.
When to Use Which
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.