Symptoms
In a Microsoft Exchange Server 2013 environment, when you restart a database availability group (DAG) node that contains active database copies, the healthy copies on other DAG nodes are not enabled. Meanwhile, event ID 4999 for MSExchangeRepl.exe and MSExchangeDagMgmt.exe are recorded in the Application log multiple times until the restarted node has completely restarted. While this is occurring, Windows clients may be disconnected.
The following events are recorded in the Application log:
Cause
This problem occurs because of an "out of memory" issue for remote procedure calls.
Resolution
To fix this problem, install Cumulative Update 12 for Exchange Server 2013 or a later cumulative update for Exchange Server 2013.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminology that Microsoft uses to describe software updates.