I ran into this problem few days back, I was not able to run the builds because the Build Controller was showing Status as Unavailable.

It was showing the below exception:

There was no endpoint listening at http://fullmachinename:9191/Build/v3.0/Services/Controller/2 that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details.

After trying out few things, I looked at below Build Service Properties.

Then, I did below modifications to the Build Services Properties:

1)      Changed the Local Build Service Endpoint(incoming) from

http://machinename.domain.com:9191 to http://machinename:9191

2)      Changed the Connect to Team Project Collection (outgoing) from localhost to machine name. http://localhost:8080/tfs/defaultCollection to http://machinename:8080/tfs/DefaultCollection

After that Started the Build Services and it fixed the issue, the Build Controller was showing Available Status and was able to run the builds.