Couldn't Find a Suitable Server Error While Alone

Okay, so basically; about four days ago I got on to play as I normally do. I fired the game up, and for some reason I instantly got the error message “Could not find a server that was suitable for all members of your fireteam.”
Problem was I was alone. And it hasn’t gone away for FIVE DAYS. I tried messing with my internet. I tried returning to a wired connection (I was using a wireless for a bit and I had massive lag spikes earlier but now I cant even play). I uninstalled and reinstalled the game. Nothing’s helped.
I have no clue what happened…I can still sell REQs and stuff I just cant connect to the servers for some reason…
Seriously. Someone, anyone? Got a solution for this? Or am I straight bloody doomed here?

Additional edit, here’s what work and what happens:
My NAT says open. I’ve screwed with my router and all that.
I finally got the Teredo issue fixed but I STILL can’t connect to the servers.

When I start up the game, I don’t get the Message of the Day. I can access my REQs, my armor, and change both of those around (I sold 10,000 points worth to get some packs that got me the new Lord of the Fries skin and a couple emblems), but I can’t go into Arena, Warzone, or Forge.

Addtional edit: It seems I can’t join parties either. I’ve tried three times and it says “your network settings are preventing party chat”. So it might be my internet.

I have the same problem except I haven’t been able to play multiplayer sense I got the game

Great…it used to work fine for me.

I had this problem near launch, after the first 2XP weekend happened, the server problem happened. Ive tried many things, blogged, and updated, till I fixed the issue on

This Thread. Port Trigger Setup for opening NAT on Multiple Xboxs worked for me. I think you should try it even if you only have one xbox, it may work for you.

Good Luck