I just successfully activated an old copy of Windows XP I had installed using the toll free U.S. phone number listed in the activation dialog (888-571-2048), so it's possible the issue was with the German number and not phone activations in general.
I just successfully activated an old copy of Windows XP I had installed using the toll free U.S. phone number listed in the activation dialog (888-571-2048), so it's possible the issue was with the German number and not phone activations in general.