We use Exchange 2010 SP2 on a Windows Server 2008 R2 box. Constantly throughout the day people here/outside the office are asked to enter their usersnames/passwords. It syncs with the AD account info.
I know there's an issue when users are wireless and they unplug the physical LAN. even though the connection is maintained while it defaults to the physical LAN it kicks back the usersname/password prompt. (They all use Outlook 2010.)
Sometimes the phones (droid x/iphone ect) prompt as well.
Has anyone experienced this issue?