13. E-mail at a Glance: Deciphering Error Messages

If an e-mail is returned to you, most likely it will contain an explanation.

• User unknown: The message arrived at the mail server, but the server couldn't find the recipient. Check the user name part of the e-mail address for errors and try sending the message again. Also, double check the domain name to ensure that you are sending it to the right organization.


• Host unknown: Your mail server could not find out the server's computer address based on the domain name. Check the domain name in the e-mail address for errors and try again.


• Message hasn't been delivered, but will try again. Your mail server failed to deliver the message, but will continue to resend it. This error message indicates a temporary communications problem that may clear up by itself. For example, this message is generated when the recipient's mail server is not functioning or is disconnected from the Internet.