The name of the remote machine was not recognized as a valid hostname. This is usually a result of mistyping or using an incorrect hostname. Ocassionally, it is the result of name server timeouts or a misconfiguration of our mail system. The user on the remote machine is unknown. Either the user account is no longer valid or the account name was incorrect.
Remote machine is down.
The mail system will attempt to send mail to a remote host for up to three days. Message could not be delivered for 3 days Message will be deleted from queue 9. In solaris 2, mail does not work - never has, probably never will. Use either mailx or Mail if you want a command line interface into email. The GUI mail programs available are dtmail, mailtool, and xmh.