Recently an employee brought this annoying little issue to my attention. It seems when he responds/opens certain emails he gets a login screen that says connect to....blah blah. No matter what you enter in it keeps coming back up.

However, if you just cancel it or click ok enough times it goes away and you can continue to work. Why would this happen and how come it doesn't seem to actually affect any of this persons work.

Some things I took note of was that he changed his email address(which was done through active directory), but still logs in as his old login. Would that have anything to do with it is outlook just confused as to who he is or is this some stupid bug in Outlook or Exchange?

I also noted that when I opened up his email I to was prompted for a login/password, but by simply canceling it, it goes away and I can continue to work. Any ideas?