Symptoms
In a Microsoft Exchange Server 2016 environment, you can’t access your mailbox because of the following error message:
X-InnerException: Microsoft.Mapi.MapiExceptionRpcServerTooBusy
Cause
This issue occurs because there's an infinite loop that occurs when a read stream is opened on a column-based property. When the stream is opened and used, another write stream is opened off the same message instance where that stream is truncated. Internal state in the PhysicalColumnStream object becomes stale and is never refreshed. Because the instance believes the stream is still much longer than it really is now, it loops forever trying to read more data that's not there.
Resolution
To fix this issue, install the Cumulative Update 14 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
References
Learn about the terminology that Microsoft uses to describe software updates.
