Child domain Outlook clients prompts to authenticate to all other chil

[ceez]

Hello fellow msfn'ers... I have an issue with outlook clients and exchange authentication.

Our outlook 2003 clients located on our child domains get prompted to authenticate whenever they first open outlook in the morning (or any time afterwards in which they close OL and open it again).

We have 1 forest with 4 child domains using Exchange 2003 SP2 & Server 2003 Enterprise SP2+R2

mydomain.net

accounting.mydomain.net

baftl.mydomain.net

orlando.mydomain.net

newyork.mydomain.net

The exchange front and back end are located in mydomain.net

Again, this only happens to child domain users accessing their client, and all the users have mail enabled AD accounts

ie:

User in accounting.mydomain.net opens outlook 03, the authentication window will prompt to authenticate to baftl.mydomain.com, click cancel and it re-appaers asking to authenticate to orlando.mydomain.net, this process continues down the list until outlook just opens successfully. All email use thereafter works perfectly.

This does not happen to users in the root domain (mydomain.net), outlook opens fine.

Any idea where we can look to fix this problem?

Thanks for reading,

Ceez