google-drive-api - Why do I get a 500 error calling Changes.Get

Question

I am trying to call as per instructions https://www.googleapis.com/drive/v2/changes/changeId

and my client is authenticated (as verified by calling different methods).

I get the following 500 error response

Google.Apis.Requests.RequestError [500] No individual errors

Any idea what this might be? By 500 I take it to mean an issue at the google end.

Here is my code that uses the .net sdk

        var changeRequest = service.Changes.Get(id); 

        var changeResult = changeRequest.Execute(); //fails with 500 error