I logged into some maps yesterday and they would never start. Today the same thing happened with one of my map created with UEFN. The game does not start, i had to try 10 different lobbies to finally find one that started the game.
Maybe disabling the auto-start would made it work?
I have the same issue. I dont know what to do. Everything was fine before 
Also in game I don`t have “Start Game” button. When I press start game in UEFN nothing happens(no errors at all).
Do you have world partition enabled? In my bigger projects that have it enabled in I’m getting the same issue. I think it stems from the client not finding the island settings device for some reason.
It was disabled by default. I tried enabling it, but no changes. Still no start game button…
I found fix on reddit, thanks to user who provided the solution. If you have same problem you need to spawn new island settings device.
that is not a fix in every circumstance. And is not working in my case. The only time it “fixes itself” is when i disable streaming which is certainly not a fix.