After launching on Ipad, a white screen is seen and nothing happens, or the app loads and stays on "signing into Xbox" screen forever.  My son is crying and saying we have horrible internet and that it loads fast / doesn't get stuck on the white screen at his friends house on this same ipad.  I ran a speed test in safari and it shows 15mbps down, 6mbps up.  The internet is fine.  Please help.