After configuring the Azure Back Sync in the Active Roles Synchronization Service, attempting to perform a synchronization fails when attempting to sync Contacts with the following error:
The Azure Back Sync step for Contacts fails with the error: The role assigned to application xxxxxxx-xxx-xxx-xxxx-xxxxxxxx isn't supported in this scenario. Please check online documentation for assigning correct Directory Roles to Azure AD Application for EXO App-Only Authentication.
The User and Group sync steps complete without error.