This page details some of the issues users may find when using the Mimecast Synchronization Engine (MSE), together with the cause and reolution
Q: What does a "Failed to execute main procedure" error in the ADR task log mean?
Applies To: Mimecast Synchronization Engine 18.104.22.16817 and later
Cause: The directory tab is incorrectly configured for your environment on the Mimecast Synchronization Engine Site Configuration Application | Accounts tab,
Resolution: Review your configuration. Check you have specified the correct directory type set for your environment. If you have an On Premise Active Directory, select "Microsoft Active Directory", if you are using Office 365, select "Microsoft Office 365 Directory". More details can be found at the Enable Active Directory Sync using the Mimecast Synchronization Engine page.