Exchange 5.5 with Outlook 2003

[salvatore11]

We run Exchange 5.5 and up until now all clients have used Outlook 2000. Recently we have new systems coming in with Outlook 2003 and when I run through the set up, I put in our Exchange Server name and user name and click "Check name". The user name is found but the Exchange Server changes to a different server on our domain. I try using the IP of out Exchange Server and same problem, the name switches to this other server. If I remove Outlook 2003 and put in Outlook 2000 on the client, all is well. I have been working with Microsoft support for three weeks on this and have gotten nowhere.

Thanks in advance for any help.