I can't join friends game session nor play online

Hello

I bought the game 10/6 2015 and my exprience with it so far has been horrendous. The Campaign works perfect solo as well as in local split screen and is where I spend most of my time in the game now. However, I have major problems with the online features of the game. Yesterday I tried to play the Campaign co-op online with some friends but it was impossible for me (and them) to join each others game session. The only thing that happens is that a message appears which says “Connection failed: Your connection to the game session has failed, please try again”.
It is also next to impossible finding a game online. The only mode that seems to work is team slayer and even that only works on rare occassions. When i try to find a game it says “searching for players” then “player found” and finally “connecting to session” before restarting all over again. It seems to be stuck in a loop. Sometimes it works but since you return to the main menu after each game (which is ridicolous), I get stuck after just playing one game.
I’ve tried to reinstall the game, erase local saving files and start again, reboot the Xbox and I have checked that my NAT-type is open. Nothing worked. My friend did manage to join my game session once, but it has not worked before that nor after and we have tried many times. I’ve searched the internet for a solution but without success. Some people solved the problem by uninstalling the wireless display app, but I have not found such an app on my console. My friend seems to have no problem finding games online but can not join my game session nor can I join his, which makes me belive that the problem is with me. Can anyone please help me on this matter?

I’m aware of the disastrous history of this game but it should have been fixed by now. It has been more than half a year. When one pays full price for a product, one expects, as a costumer, that the basic features of the product works. This is absolutely preposterous. My relation with 343 industries has been damaged beyond repair. I simply will and can not trust them in any future games (bye bye H5).