We have user accounts with multiple email addresses on our network. For some reason we are not recieving emails on 2 of them now.
For example we have firstname.lastname@example.org and that account can also be emailed at email@example.com and @zzz.com
For some reason I can no longer recieve emails at lets say the @zzz.com addresses You get 550 mail box not available.
All the domains are current and not expired and the MX records are all correct. The email gets to our spam filter but cannot be delivered to our server.
I tried a telnet test to send an email to that account and from inside the network that works but from outside I get 550 mail box not available and I did add the outside IP address to the SMTP server's connection list.
Any thoughts on what the problem may be. The accounts are still receiving email on the other domains and its all one Exchange server.