In a Microsoft Exchange Server 2013 environment, you notice that the Microsoft Exchange RPC Client Access service (MSExchangeRPC) crashes and returns a System.NullReferenceException exception. This problem causes connectivity issues when users try to connect to their mailbox.
This problem occurs because the null value exception is not handled correctly in Exchange Server 2013.
Exchange Server 2013
To resolve this issue, install Cumulative Update 21 for Exchange Server 2013 or a later cumulative update for Exchange Server 2013.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology that Microsoft uses to describe software updates.