I have upgraded an office to a new server with Windows 2003 and Exchange 2003. Generally, everything is working well. This was a fresh install with no migration. Email was exported to a .PST and then imported with Exmerge. There are 4 or 5 domains that the users can no longer email to. They had worked fine with the old NT 4 and Exchange 5.5 system. No DNS or router changes were made. Any ideas would be most apprecaited. Thanks!
This is an example of a bounce back. (We are able to email this user/domain from Yahoo and the like)
The following recipient(s) could not be reached:
'firstname.lastname@example.org' on 11/3/04 10:29 AM
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<pegasus.lifespan-roch.local #5.5.0 smtp;550-EarthLink does not recognize your computer (18.104.22.168) as connecting from an EarthLink connection. If this is in error, please contact technical support.>