I am running into an issue. I just implemented a new installation of Exchange 2010 into the company here. They were using another hosted pop mail solution so no issues with legacy email systems. Everything is running just fine, but I am getting random users that keep getting prompted for their username and password. It keeps popping up with a "Need Password" in the bottom right corner of outlook and once typed in they are fine. Next time they start they may get prompted again. Even if you check to remember password it will still pop up again. I am using RPC over HTTP and am thinking it may have something to do with that but not sure. Can anyone help me resolve this.