Update: Xbox Live service has been restored. A spokesperson for Microsoft told Polygon, "At 10:50 a.m. PT today, the Xbox Live Services teams were making some networking changes that resulted in a connectivity error for all users in accessing Xbox Live and Xbox.com. Our engineering teams quickly reversed the change and all systems are restored."
A tweet set out around 2.20 p.m. ET today stated, "We have run into an issue with the Xbox Live service, and are currently investigating. Stay tuned for status updates."
Polygon has called Microsoft for an update and requested an explanation.