Some of Scheduled Custom Reports are in a "Defined" state with with Status message of "Service Restarted" and the report does not run or get emailed.
The ReportService.log contains Errors like:
NetQoS.ReporterAnalyzer.Business.ReporterToQueryServicesException: Communication error through COM. Report may already be Queued. ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Runtime.InteropServices.COMException: Unspecified error (Exception from HRESULT: 0x80004005 (E_FAIL))