Can't Hear People on Xbox Live Even With an Open NAT

BTW, I hear the rest of the gameplay just fine with no issues. I just cannot hear opponents and/or teammates while I'm online. Again, happened from one day to the next without me knowingly changing any settings on my xbox or fios (internet) connection.

Update: all necessary ports are indeed set up on my router and still no voices

My NAT is open and I still can't connect or hear friends

Same problem. Also notice that I can't hear some people in game chat (their mics light up, so I know they're talking). Seems to be an issue with people wearing headsets. Kinects still go through lol. Also, my NAT is Open. This is bogus, Xbox.

Have you tried connecting your Xbox 360 directly to the modem via an ethernet cable? That can help determine whether it's an issue with your router or not.

Just tried this, and my NAT was indeed open with this setup, so it does appear to be the router. Oddly enough, though, when I put it back to wireless, it still said my NAT was open, even after restarting my router and Xbox.

The only thing I don't get is that now I can't see certain people's status on Halo: Reach. There are two players whose stats I cannot see and parties I can't join (in-game parties, anyway), one I know has an open NAT.

I even reset my router to factory settings and it's still the same thing. Open NAT but can't view their stats or join them.