Recently I added a second domain to be looked after our Exchange 2003 Server.
1st Domain abc.com
2nd Domain xyz.com
I have configured MX records to point to the Exchange Server. And I have even placed a recipient policy for xyz.com in Exchange Server and checked that the server is responsible for all mail delivery to this address.
However when I go to send an email to that address firstname.lastname@example.org I get the error message:
Diagnostic-Code: smtp;550 5.7.1 Unable to relay for email@example.com
I can't figure out where I have gone wrong. Surely the recipients policy entry covers this.