I recently added a Window Server 2008 to our AD Environment. We have been running Exchange 2007 for about 2 months. Since the addition of the 08 DC, and maybe this is a co-incidence, when we create a new user and that user opens Outlook 2007, Outlook logs on to the server, but does not authenticate the user.
Any ideas why the Exchange Server doesnt authenticate the new user? Oh, BTW, when that user uses OWA, they can log on fine.