I have a client who utilizes just one mail account for his whole staff. They've been doing this for years now, and haven't had many problems (besides the obvious mailbox size, etc.). We upgraded the Exchange Server to 2013. Now every 11th user or later who tries to open Outlook with that account cannot connect to the Exchange Server. It tries to make the connection, but ends up saying its disconnected. As soon as I have another user logoff, the user whose having the problem can connect.
At first I thought it was throttling, but I disabled it and the problem still occurred. Employees are using Outlook 2010, but I also tried 2013 with the same results. Running a test, while Outlook wouldn't connect, I set it up to a different user account and it connects fine, as soon as I went back to the original account it failed once again.
Does anyone know of a limitation like this? If so, how do I fix it?