I have a user that got a BB and started using bis to get her email/calendar/etc from our Exchange 2003 Server. As soon as she activated this I am getting logon failures in my Event Viewer on the Exchange Server. These are event id 680, and the error code is 0xC0000064 which according to MS "the account does not exist". I get these error messages every 2,5, and 16 minutes for over a year now. Another user just got a BB and the same thing is happening with that user. One is using Alltel the other is Verizon.
Neither user is experiencing any sync issues, just filling my Event Log. Any ideas why this could be happening?

Thanks.