SMTP 214 Help Message vs 551 User Not Local
SMTP 214 (Help Message) is a 2xx Positive Completion response, while 551 (User Not Local) 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, 551 means that the recipient is not local to this server and the server does not accept mail for forwarding. Unlike 251, this is a rejection — the server will not relay the message.
Mô tả
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.
Khi bạn thấy mã này
After sending the HELP command to the SMTP server. The response lists available commands or provides usage details for the command you specified.
Cách khắc phục
No fix needed — this is a normal informational response. Use the provided help text to understand which commands the server supports.
Mô tả
The recipient is not local to this server and the server does not accept mail for forwarding. Unlike 251, this is a rejection — the server will not relay the message.
Khi bạn thấy mã này
When sending to a recipient that has moved or whose mailbox is hosted elsewhere, and this server refuses to forward the message to the new location.
Cách khắc phục
Check the server's response for a forwarding address and resend directly to that address. Update your contact records if the recipient has permanently moved to a new mail server.
Sự khác biệt chính
214 is a 2xx Positive Completion response, while 551 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 551: The recipient is not local to this server and the server does not accept mail for forwarding. Unlike 251, this is a rejection — the server will not relay the message.
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 551 when when sending to a recipient that has moved or whose mailbox is hosted elsewhere, and this server refuses to forward the message to the new location.
Khi nào dùng cái nào
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 551 (User Not Local): Check the server's response for a forwarding address and resend directly to that address. Update your contact records if the recipient has permanently moved to a new mail server.