Outlook problem

[cking]

we connect to outlook through the exchange server, everyone pulls the username and password correctly no problems, one person when ever they open Outlook it asks for username/password/domain they are connected to the domain and when they supply the creds they are fine until they close and reopen it. tried uninstalling reinstalling outlook/office, changeing the profile, and several other things with no luck, is there away to shut this off?

[icecube]