Originally posted on 08/17/2018:

I had same problem for a long time. Try this: after you click on the game, in the new window left click on the lock icon in the address bar (which is left of the word "Secure"). Then within that go to site settings and in that, change the "Flash" setting from "ask" (which is the default) to "allow". That fixed the problem for me. Worth trying if you haven't yet.