Why won't modern warfare 2 work on my ps3?

I really don't know what else I can do to make this work, so maybe someone here can help me out.



There's nothing wrong with my internet settings (I checked and everything is fine) and my NAT type is generally OPEN. Other games, like MAG work for me so this particular problem boggles my mind.



I can log into the playstation network, see all my friends online, even send messages to them. However, if I try to invite someone to my party, or accept an invitation, the same error: "Cannot connect to host" comes up. When I try to find a game, it gets stuck searching for games and cycles through "potential" games.



Sometimes everything will work fine with no problems, but more often than not, I am getting this problem. I can't play the game because I cant join a friend's party, find a game, or even join a game that's in progress.



I've opened up my ports and nothing has happened. Does anyone have any idea what the problem is? Has anyone experienced something similar?Why won't modern warfare 2 work on my ps3?
I used to have 1 friend that I could not connect to no matter what I tried. I simply powercycled my router and everything was fine afterwards. If you have a reset button you could try that too. I have since found what was causing my issue though. It sounds like your router is not accepting random internet requests. Try disabling your firewall on your router and see if that helps. I know you said you opened the ports but if the firewall is active it may block some random requests.