Can’t save Fable – The Journey

Looks like it could possibly be your router config. Did it work previously then stop either randomly or after an update? There's some surprisingly sane information about ICMP here (ignore the "Best Answer" and look at the other longer one).

If you know your way around a router then you could stick the xbox in the DMZ. If that solved your problem you could be pretty sure your router config is the issue and could then refine it from there.

It would be worth trying a wired connection also, if you could borrow 20m of cat 5 off someone.

When you say other players do you mean friends or just players in game? If it's in game is it for all games that you have tried?

This probably can occure when your NAT is "moderate" if that is the case that can prevent you from talking to other people, this has happened frequently for me. Try doing a test of your network settings. If you can resolve that issue then you will probably be able to use the "talk" functionality.