I have a setup were I'm replacing our old Exchange 2003 with a new Exchange 2003 due to hardware. Both servers are up and running, I transferred one account over to the new server as a test - went fine. Outlook 2007 was updated with the new server name. Contact list work fine and I'm able to receive email internally and externally. I can send email to external address, however when I try to send to a contact on the old server, it gets rejected. I get the following error: There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <OLDSERV.ourdomain.ca #5.5.0 smtp;550 Requested action not taken: NUL characters are not allowed.> There is a subject line and message, so nothing is blank. The current setup is: First Routing Group/Members OLDSERV NEWSERV

I forgot to mention OLDSERV 192.168.0.10 SMTP is configured to use port 8025 (we have email filting software on port 25) NEWSERV 192.168.0.11 SMTP on port 25 Joe