When this issue occurs, a System.NullReferenceException exception is thrown with the following error message:
Object reference not set to an instance of an object.
This issue occurs because the ArchiveDomain property of the Active Directory object for users is not set or is empty. When the RPC Client Access service tries to compute the identity of the remote archive mailbox, the ArchiveDomain property is used, and it cannot be handled correctly. Therefore, the crash occurs.
To resolve this issue, install the following cumulative update:
2961810 Cumulative Update 6 for Exchange Server 2013
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.