Have Exchange 5.5 running on Win NT 4.0. Have 2 domains and 2 MX records pointing to this one Exchange server. Recently put in a WatchGuard x1000 firewall. No problem with emails until couple of weeks ago (I was just notified today). One of the client company cannot send us emails. They get the following message:
The following recipient(s) cannot be reached:
'User' on 4/14/2004 4:48 PM
550 5.1.1 unknown or illegal alias: user@domain.com
Nobody else have problem sending us emails...just this one company. Any suggestions? And what is this '550 5.1.1 unknown or illegal alias' mean?
Thanks in advance.
The following recipient(s) cannot be reached:
'User' on 4/14/2004 4:48 PM
550 5.1.1 unknown or illegal alias: user@domain.com
Nobody else have problem sending us emails...just this one company. Any suggestions? And what is this '550 5.1.1 unknown or illegal alias' mean?
Thanks in advance.