Have you disabled plugins/addons/extensions (the likly cause if you can play them when not logged in, but can't play them when you are logged in).
If that isn't it, what browser do you use? Does it happen in another browser? Can you provide a screen print (scroll all the way up so that we can see your profile bar, and make sure the window is large enough to see below the game area)?
I didn't find the right solution from the internet.
