Microsoft has acknowledged and is responding to an issue preventing Xbox One owners from signing into Xbox LIVE. Though it's not clear exactly what is causing the problem, Microsoft assures they're "on it," and working on a fix.
As of right now, it appears as though only Xbox One is being affected. According to the support page, users are unable to sign into Xbox LIVE — which is a pretty big deal considering many games, like Call of Duty: Advanced Warfare and Destiny rely on being logged in for the full multiplayer experience.
Destiny developer Bungie has also responded, tweeting the following message: "We're currently investigating issues preventing Xbox One users from signing into Destiny."
