We are running SBS 2011 on a Dell R420. I had to switch from a software RAID to a hardware RAID controller. Due to poor performance. I created a Windows Server Backup. Installed the new controller and re-imaged from the backup. The server seems to be working fine and mail flow is working, but all of the users cannot connect to the exchange server. On users PC's I have tried to repair the Outlook account and I tried creating a new profile. Both of which seem to work, but when opening Outlook it does not connect.