I'm having a bit of trouble adding a hosted Exchange account to Outlook 2010, we have recently acquired Office 365 with exchange online, and its all set up now. its working fine on mobile devices and everyone can enter via Outlook Web App. its all working. the problem is adding the exchange account to outlook 2010, the problem is it keeps on asking for credentials over and over again, the other problem is that the issue is not persistent across all the workstations, it works on some and doesn't work on most. I have tried adding a new profile and removing old accounts, nothing seems to work.
The workstations that I'm having problems with are running windows XP SP3, any help will be greatly appreciated. Thanks in advanced.