Maintenance workitem "ShadowService.Maintenance.Workitem" (ID: 139) has failed. Health Manager has detected it is either set to run once and failed, or has been failing consistently. Maintenance workitem failure could cause monitoring gap and should be investigated.
The error message from the last result is:
System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Exchange.Shadow.Common, Version=
15.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.