We are currently running Exchange 2013. We had a user who left our company, therefore, we will disable his/her mailbox by ECP. He/she re-enter the company, we mount his/her mailbox to the AD account. He/she left again, therefore, IT support disable his/her mailbox again. But this time have difference, we cannot see his/her mailbox again on the "Connect a mailbox".
Any expert knows where's the mailbox going? And why this happens?
Thank you very much.