Hi. I heard that verifying the game cache can fix the trouble. First, give it a try. If it doesn't help, go to the launcher. So, as you have a pirate version of the game, indicate it (revemu, revloader). Then find the server you need, to the right of it there will be an inscription "connect". Try it too. If this does not help, I can advise you to download the latest version of the game from this site. https://se7en.ws/left-4-dead-2/All updates come pretty quickly there.