You aren't alone if can't sign into or launch games on Xbox One right now

[Windows Central]

There's another outage.
A few days ago, there was a major Xbox Live outage which resulted in Xbox One consoles connected to the internet refusing to move beyond a black screen. While this was quickly resolved by rolling back a server update, many gamers were disappointed that this occurred to begin with. Ever since that day, Xbox Live hasn't been operating normally and this morning the service was hit by another outage.

Full story from the WindowsCentral blog...