Halo 3 party up problem only i have

[Bradley T]

I have a problem with my router or something it wont let me party up with my friends even though i have an open NAT

 

[Shadow]

Sometimes it depends on who is party leader. Try having you be the leader.

 

[Kene]

sign out then sign back in..if that doesnt work then turn off ur xbox then turn it back on then try again....it should work cuz it happens to me frequently