Ok guys for some reason i cant play multiplayer i keep getting the same message “failed to join session” this is when i try to join friends and even when i try to join a session alone i have even tried to create my own session with no success any ideas ?
Also my nat settings are open and my connection is perfect .
Usually when mine does this I back out to the dash board, hit the start button on Forza, and quit the game. Then restart from scratch. If that doesn’t work I shut down the xbox fully, unplug from the wall for a moment, and let everything fully restart. If that doesn’t work I sit there and hit join session for as long as it takes and sometimes it changes it’s mind and lets me in. That is rare though that it goes that far.
i have tried reseting everything even restored the console to factory settings and still nothing .
Just had xbox customer support on the phone and they said there are no issues regarding my account or console .
With the above advice, you could also unplug your router for a few minutes as well. Even if the nat is open and you have good connection speeds, your router can still cause issues with your connection.
Go to your router settings and make sure that IPSec is enabled.
Just do what I do, curse at the thing and threaten to smash it with a hammer. Works for me… 
Seriously, I seem to have connection issues all the time any more. I just reboot (or whatever its called when you hold the button in for 5 seconds) and it almost always corrects whatever the problem is. Its very annoying, but it does work.