If you wanted to show off your exploration of Fallout 4's wasteland or your cool skills in Rise of the Tomb Raider on your Xbox One console today and found that you can't do that on Twitch, you are not alone. There is apparently an issue with broadcasting on Twitch via Microsoft's console at the moment.
In a post on its Twitter support page, Twitch stated:
"Xbox One broadcasters: We're in active investigation with Xbox on this issue. Thanks for your patience"
Naturally, we will update this post when things are back to normal.
Source: Twitch (Twitter)