A recent update broke game starting. I have not tested all games, but I think it is broken for everything but Guild of Thieves which has been moved to the new interface.
Currently, you can create games and people can join, but the game will not start once everyone has joined.
Unfortunately, this does not appear to be a 5 minute fix. I will dig into this tonight after work. I suspect I will be able to return things to normal by tomorrow.
Sorry for the inconvenience.
Jeff