Same thing for me. Played for 3 hours and the game crashed. When i re booted i couldn't find any servers. I played around with filter settings, checked my firewall, re-installed the game even typed in a server address to direct connect and then it got stuck on waiting on host every single time. Joined my friends game through the steam tab - again got stuck on wait for host screen. waited an hour on one the rest i just kept trying. This was over 6 hours ago now and still no servers....

exact same issue for me. I have done everything you have said and it still doesn't work. Cannot join a game through the join a friends game in steam tab either as i get stuck on the "wait for host" screen. Is there any fix for this yet?