Hmmmm, in fact, when I open the JoiApp, always appear a message: "you're using a device with Android 11 or later. Some file operations are limited and extremely slow on these versions. This might cause lags and Aplication Not Responding (ANR) dialogs." Despite that, I never had any problems because of it. And yes, I tried reopening the game, it never loads. I also just found out that, even without being on the mission, the yuru yuri game always cause this problem.
Okay, I have found a bug, I don't know if it is the one that prevents you from playing. To be confirmed:
Before the game fails you, the five girls are together, celebrating that it is finally the official opening of the club. So, Katsune says that the protagonist will be the first to try the games. Then the screen goes black and the game no longer continues.
Is it so?