For the past hour, Xbox 360 and Xbox One owners have reported that they've been unable to connect to Xbox Live. Consoles are responding with the 80151909 error code — it warns that an Xbox Live profile has failed to download — when users attempt to sign in. Our own attempts to sign in to Xbox Live from consoles and through Xbox.com have been unsuccessful.

http://www.polygon.com/2014/12/1/7317975/xbox-live-offline-hacking-group-lizard-squad

http://venturebeat.com/2014/12/01/xbox-live-down-intermittently-hackers-take-credit/