Domino refuses to sent external mail

[sjohnson]

My old Domino server (a windows XP machine!) is now very tired. We have purchaced a new Server 2003 machine.
Following the moving of the notes data (see below for method used) the new server refuses to send any external email. Internal mail and incoming external mail route correctly - just outgoing external email.
If I move the install back to the orginal macine and fire it up - Hey Presto! all working again.
Any ideas please!!

Here is the message I receive:
"05/05/2008 23:37:11   Router: No messages transferred to HOTMAIL.CO.UK (host HOTMAIL.CO.UK) via SMTP: The server is not responding. The server may be down or you may be experiencing network problems. Contact your system administrator if this problem persists."
This applies to any domain.

Method:
1. Dell 2950 Poweredge 2003 Server - installed 6.5.4 server.
2. Stopped after 1st part of install (ie did not start nserver to proceed to configuation menus)
3. stopped old server
4. swapped IP address over
5. copied program and data directories to new server started new server

All data and drive paths remained the same