Won't Let Me Join Party

It may be your NAT settings.
It's the same with me and one of my friends. We can't connect to any matches or parties when we are by ourselves. But if someone else is in the party or match, we connect just fine.

There's a website that will help you, however i can't remember the name of it and can't find it in google.
I'll post it if i find it.

Alright, i've found 3 sites, mind you i think it takes about a half hour to do, and i haven't tried it before, but it should work.

Try these links.

Previous neo thread with the same issue:
Here

Noddegamra:
Here

Probably the one that you have the biggest chance with - PortForward
Here

Hope i helped.

If your stil having troubles with it, let me just say that i had the same problem. I got a xbox in the first place just to play online with my boyfriend, and turns out he was the only person in the world it wouldnt let me connect with. We both had open NaT types and we played online with everyone else fine, but for some reason we could never connect or join with eachother on anything. I looked online and didnt find anything that realy helped, but I just finnally found a way that fixed it. Try changing your internets security settings to WEP. Mine was on WPA but it still said my nat was open, yet as soon as i changed it all of our problems were gone, and I could connect to him perfectly like everyone else. If you cant find a way to change it then search google, they have easy how-tos on changing to WEP. And the process only takes a couple mins too. Lastly, if yours is already WEP or changing it doesnt work, ask the other person to try switching theirs to WEP too. It worked fantasticly for me, I wish i wouldve known this sooner, and pretty sure it will for anyone else that has the problem too. Good luck!