Following migration from Exchange 2003 to Exchange 2010, one of our users is continually getting a prompt to login when opening their mailbox in Outlook 2007 on a machine they share with several other users. Other people using this machine don't get the error and if the user opens their mailbox on their personal office machine they don't get the error. They are prompted two or three times to enter their credentials but it doesn't accept their password. It then connects to Exchange anyway but it throws up a certificate error. I've tried both repairing and recreating their mail profile on the PC. I've also tried turning off cached mode and installing hte certificate locally. I have also flushed the DNS on the machine and I have reinstalled Office on the machine. I even tried resetting their password.
Lisa