When you run a POP3 email account in a Microsoft Exchange Server 2013 environment, the POP3 services intermittently stop. This causes users and applications not to send or receive email messages. However, after the administrator manually starts the POP3 services, users can send and receive email messages as expected.
This problem occurs because the proxy session for the POP3 Service is not handled correctly by Exchange Server.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.