EventID: 2 Channel: Microsoft-Exchange-ActiveMonitoring/ProbeResult ResultId: 479968430 ServiceName: Monitoring ResultName: HealthManagerHeartbeatProbe Error: Failed by design. Exception: System.Exception: Failed by design. at Microsoft.Office.Datacenter.ActiveMonitoring.TestActiveMonitoringProbe.DoWork(CancellationToken cancellationToken) at Microsoft.Office.Datacenter.WorkerTaskFramework.WorkItem.Execute(CancellationToken joinedToken) at Microsoft.Office.Datacenter.WorkerTaskFramework.WorkItem. c__DisplayClass2.startexecuting b__0() at System.Threading.Tasks.Task.Execute()
So why is something failing by design?! Basically this probe is testing the Managed Availability framework, including that it can run responders. More specifically, a probe that will test that monitors can become unhealthy and execute null responders.
Bottom line, nothing to worry about :)