So, i don't know why, but from time to time i can't create lobby for my map and also can't join to other lobbies. This is stupid. I should press join and create button about 10 times before it works... Really, what is the problem?
Did this occur soon after having published an update for the map? I recall an issue around 2015 where map lobbies might not be immediately available after publishing an update for that map. The solution was to wait anywhere from 5 to 120 minutes and then lobby creation could resume. Possibly it has to wait for the last active game of the previous version to end?