As if to further wind me up.... A further catastrophe has befallen me... And yes I am aware that this is a first world problem, blah blah blah. Finally got everything downloaded. Been playing Forza. The wretched thing will not connect to any multiplayer games. Checked NAT type etc, nice and open. Went on some Forza forums, apparently some routers will not work with the damn thing. Some fancy new net code..... You can guess at the look on my face right now. Virgin media and the Super hub 2 have some work to do it seems. This could be the end of the whole thing for me. No online gaming removes much of the point. Gutted.
This may or may not help you but I had a similar problem a week ago. And my NAT was already defaulted to open. Xbox One requires you to open up port forwarding for several ports. Once I did that I was able to connect to parties and play online.