In this case, you need to manually add Modern Warfare to the list of bypassing the firewall. However, there are some situations where it fails to trust your programs and thus blocking access to your Internet. Windows Firewall is designed to protect your system from malware attacks. Allow your game through Windows Firewallġ.You may not need to try them all simply work your way down the list until you find the one that works. To help you out, we’ve put together some fixes. Issues like the game not launching are plaguing some users. This is the same with Call of Duty: Modern Warfare. No matter how well a game is optimized, it’s never immune to bugs or glitches.