A large part of the Xbox experience comes from Xbox Live, which is pretty much required to do anything on Xbox platforms- sharing your profiles and achievements, playing online, communicating and socializing, or even just using apps. So when Xbox Live goes down, or has issues, it can jeopardize the entire Xbox experience on your console.
Such as is happening now.
Currently, Xbox Live is creating issues with users trying to buy or download content, and with trying to access the Twitch app. The phenomenon seems to be global.
A statement on the Xbox Live site reads:
“Xbox members, we know some of you are unable to watch television seasons that you’ve already purchased from Xbox Video, and we’re diligently working to correct this issue right away. We appreciate your patience during this process and will update you again when we have more information.”
Hopefully they can get this up and running again soon, because they’re really not making a great case for the ‘power of the cloud’ otherwise.