Using the default code shown below from my windows application, I am expecting a IE popup for authentication to Visual Studio Team Services (was Visual Studio Online):

```
TFS_ServerUri = https://myaccount.visualstudio.com/DefaultCollection
tpc = new TfsTeamProjectCollection(new Uri(TFS_ServerUri));
tpc.EnsureAuthenticated();

```

But I am getting "You are not authorized to access..."

Any idea how to get the pop-up.