This error follows a single user out of 180+ users/mailboxes in my domain.
I'm able to login as myself on his machine and Autodiscover and everything work fine. I log in as him on my machine, and the error follows him.
I'm at a loss... this user is currently working with Exchange 2013 and Outlook 2013, on his old machine. New PC time though, and the issue seems to follow him now where ever he goes.
any ideas?
it seems to be Exchange side, since it follows the user... but I'm not sure what to check, and why it's still working on his old machine.