“X-InnerException: Microsoft.Mapi.MapiExceptionRpcServerTooBusy” error when you try to use a mailbox in Exchange Server 2016

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.