Facebook Instant Games: Stuck at loading

We're trying to put our HTML5 game on Phaser into Instant Games. The game loads when opening from PC browser by https://www.facebook.com/instantgames/... link. But whrn trying to pone the game from an Android FB app, the loading progress starts but gets stuck at some random figure at about 70-90%.

Have anyone dealt with something like this? Or maybe you know a way to debug it?

Well, the progress gets stuck simply because there's some exception behind it. It may be a server responding with 500 or it may be a JS exception. To find out the exception that was behind the problem we just opened the game at m.facebook.com with DevTools.