I have been traveling a month with very limited WiFi access and the WiFi access I have has not let me sign into Xbox music services. What I have found is that I can no longer play music on my Surface. This is very disappointing as that is one of its primary purposes. Yes the music is on the Surface itself and is not being streamed. It simply wants to sign in, I am guessing to authenticate my account, and when it cannot, it does not give me access to my music.