Exchange 2013 Managed Availability Event ID: 4 Errors: "Directory Object not found"

So an Exchange installation was having some strange issues. The main symptom was that users would get a busy signal when trying to dial into the UM service on Exchange. Checking the server all the services were started but doing a netstat showed tcp 5061 was not listening. This is odd since all of the UM services were started, this is odd but not unheard of in 2013 where Managed Availability can kill a portion of a service.

Doing a check of the server health by running “Get-ServerHealth %server% | ?{$_.AlertValue –eq “Unhealthy”}” showed that the UM.CallRouter was unhealthy and offline. There were a few other’s showing unhealthy also which was odd since the client didn’t report any other problems.

The event logs for Managed Availability monitoring are located in the Event Viewer under Windows Logs > Applications and Services Logs > Microsoft > Exchange > ManagedAvailability > Monitoring

In the logs there were a ton of event ID 4 errors. Looking further they all seemed to be complaining about the same thing: “Directory object not found. Active directory response: 0000208D: NameErr: DSID-03100213, problem 2001 (NO_OBJECT)”

Here’s what the event log looked like.

What’s strange is that it thinks it can’t find the objects it’s looking for in AD. So I jump onto the DC in question and check its replication and health. Its fine, the server is fully up to date and functional. So what is it Exchange can’t find?

Taking a look in AD Users and Computers there is a container called Microsoft Exchange System Objects, which is where the objects that Monitoring Availability uses reside, however in this domain they were missing. The container had the following:

There should be a folder called Monitoring Mailboxes, but it’s missing! This is what Managed Availability can’t find in AD. So the next step is how to recreate it?

It turns out that this is one of the things that the Exchange 2013 setup does during the PrepareAD step. The server is Exchange 2013 CU3 so I went to the folder that has the extracted install files for cu3 and ran “setup.exe /preparead”

Now when we look into the Microsoft Exchange System Objects in ADUC we see:

Inside of this are the objects that Monitoring Availability was trying to find!

So now that the AD objects are where they are supposed to be I restarted the “Microsoft Exchange Health Manager” service and now the logs are clean!

Now a netstat run on the exchange server shows that tcp 5061 is open and when users call the UC system they get the attendant and not a busy signal, life is good!

The moral of this support story is that sometimes you really need to think about the things windows is telling you. Windows was upset because it couldn’t find objects in AD, but unless you really sit down and think about things you might miss what it’s really telling you. As in this case it was missing the Health Mailbox objects which caused Managed Availability monitors to break down and killed the UM Call Router.

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