Microsoft Dynamics CRM uses Exchange Web Services (EWS) to synchronize items between your application and the Exchange server. When the EWS Managed API tries to convert a property that is of type PT_BINARY, if the property's value is null, an exception occurs.
To resolve this issue, install the following update:
2936880 Cumulative Update 5 for Exchange Server 2013
Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.