During quizzes it suddenly stops. It might after 5, 7 or maybee questions. There is no way to get it running. All keys are locked and cannot be operated. Only way out is to remove the app from memory and start it up again.

Hello there! Sorry to hear about that behaviour. Unfortunately it will not be possible to reproduce the problem just with the descrption you have given. We will take a log at the debug logs on Google Play to try to figure out what might be wrong. Meanwhile a new version would be released in the coming couple of days, it might solve the problem you have.