Can`t connect to any horizon sesion

My son has been playing with me all day, he switched of his xbox and later wanted to join, suddenly he cant join a session with me or join my convoy etc. I am connected and playing and he cant at all? We restarted the xbox and game, restarted the internet connection and changed the network. still nothing. His profile is Die Farrier… Any help Please.

Having same issue myself. Been like this last half hour