Unable to join game with others

I can't get a screen shot. When I invite others to my game (or others invite me to join their game), the icon which is checked to allow friends to join disappears, and the comes back unchecked-the circle which says "joining game" also just goes away after a few seconds. This has been happening since yesterday, checked all my settings, reset xbox and router, still having problem. Party chat for voice only works normal.

fixed