MDM on Surface Pro blocks Mimecast Add-in for MS Outlook

We have recenly been trialling the MDM for MS Surface Pro's running Windows 10, we also run Outlook 2013 with the Mimecast for Outlook add-in. We have discovered that retrieveing email is not possible as Mimecast reports that it cannot connect to the cloud. If MDM is removed it works again. The error in the Mimecast logs is:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.InvalidOperationException: This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms.
at System.Security.Cryptography.MD5CryptoServiceProvider..ctor()

Any ideas?