Go on a journey of the imagination with us. You've sequestered some time to yourself and are settling down to play one of your favorite shooters. You boot up Modern Warfare 2 and try to get into a match, only to be hit with an error and essentially told that won't happen. What's that? It's actually happening, and this isn't our imagination? Well, that won't stand. Let's get down to the business of fixing it.
How to fix Matchmaking not working in Modern Warfare 2
There are several reasons for matchmaking to be a stubborn pain in the rear. So, let's go over some of the basic troubleshooting steps to work through and eliminate.
Confirm that MW2 isn't having any known issues
If there is a larger issue impacting the game, then the developer is likely aware of it and has information available. Resources like Activision's Twitter account or the Activision Support Twitter account are great places to check.
Confirm that your local network isn't experiencing problems
If you've completed step one, then the odds are your local connection and network are fine. Still, it doesn't hurt to double-check that the device you're trying to play on is actually connected to the internet. If an issue is discovered, reboot the device (PC/console) and your network equipment (modem/router/gateway) and try again.
Restart Restart Restart
This can apply to many different aspects. Back out of the lobby and re-enter it. Restart your device (PC/console). Close the game out entirely and relaunch it. Oftentimes, smaller errors can be resolved by simply restarting.
Check for updates to both Modern Warfare 2 and any device drivers like your GPU and LAN adapter if you're playing on PC. Activision won't allow out-of-date versions of the game to connect and it has been confirmed that out-of-date graphics drivers can also cause this issue.
For more Call of Duty goodies, check out Best Equipment to use in Modern Warfare 2 on Pro Game Guides.