When you use the Hybrid Configuration wizard to create or manage a hybrid environment that includes Microsoft Exchange Server 2013, you receive the following error message:
Subtask CheckPrereqs execution failed: Check Tenant Prerequisites
Deserialization fails due to one SerializationException:
Microsoft.Exchange.Compliance.Serialization.Formatters.BlockedTypeException: The type to be (de)serialized is not allowed: Microsoft.Exchange.Data.Directory.DirectoryBackendType
This problem occurs because of recent changes to Exchange Online that prevent the Exchange 2013 Hybrid Configuration wizard from running correctly.
To resolve this problem, follow these steps:
For more information about the benefits of the latest Hybrid Configuration wizard, see Introducing the Microsoft Office 365 Hybrid Configuration Wizard.
When you upgrade from Microsoft Exchange Server 2010 to Exchange Server 2013
If you upgraded from Exchange Server 2010 to Exchange Server 2013 and are experiencing the issue that's described in the "Symptoms" section, we recommend that you install the latest cumulative update for Exchange Server 2013. For more information, go to Updates for Exchange 2013.