What does the error message "550 Mail Relay not allowed" mean?

Question

This message is displayed when you press the “SEND” button in your mail client (e.g. Outlook, Eudora, etc.).

Answer

This error code is generated by the mail server to indicate that your message can-not be sent via this server. Administrators of mail servers will prevent unauthorised use of their systems so that their services are not hijacked and abused by others.

Specifically, the SMTP 550 error code is defined by RFC821 and states “550 Requested action not taken: mailbox unavailable (e.g., mailbox not found, no access, or command rejected for policy reasons)”.

To resolve this problem you have the following options:

1. Contact the owner of the mail server and ask them to allow you to relay email through it. GMS can:
   AUTHenticate users (using the methods: LOGON, MD5, CRAM-MD5 and PLAIN)
   support POP before SMTP
   and IMAP before SMTP.

2. Use another mail server (with the owner’s permission).

Keywords:SMTP, Error Codes, 550, Mail Relay, Relay, Send, Can’t send