Can not play any COOP Online

My internet isn’t the best, it isn’t the worst either.

I have added exceptions to Firewall, Antivirus, Windows Defender etc. and my social settings are set to Public any one can join my games.

When I go into social and try to join an online coop campaign I join the other persons game successfully then I get the small ‘bad connection’ icon in the top left of the screen then it gives me a network error ‘Check you network’ on every single game I join.

I have not been able to join a single online coop game since I have purchased this game.

Any help please?

My network is alright, I am connected to 4g LTE, around 12 mbps Download and 15 upload. Usually 120-180 ping when connecting to EU severs on other games.