As of 3:45 p.m. Eastern, Xbox Live is suffering connection issues resulting in "Limited" access on both Xbox One and Xbox 360. Managing and playing with friends caught the worst of this hiccup, but other services will likely be unstable until things are patched up.
"Are you running into issues creating or joining multiplayer matches?" the Xbox status page reads. "Additionally, are you having trouble joining parties or sending party invites? We're aware of the issue and hard at work to find a fix."
Fortunately, all entertainment services other than the 360's IGN app seem to be up and running. The Xbox storefront is also green across the board, but with sign-ins affected, even that may get hairy.
Source [Xbox Support]