Games may be nonfunctional for 3 reasons:
Issue on the client side - this may be caused by insufficiently powerful hardware for the given game, by obsolete software or a different problem in the device.
Network blocking - games may be blocked to load and play by network administrators on public, school and company internet networks.
Issue on the side of a game provider - Game developers may make a bug or decide to shut down the server with their game. In both cases, the game stops work.