what's with the compatibility problems?

I’m sitting at my Xbox this morning and a friend wants me to join them. The Xbox said that there was a problem with our compatibility and that I should come to www.halo4.com/nat I did and I can’t find a single thing to help me fix this situation! Someone please help?

Have you tried to reset your router/modem? if you can’t connect then one of you has a strict NAT type caused by your internet connections.