Exam mode doesn't work
I want to allow my students for the first time to use an app of GeoGebra during an exam. In Flanders it will be a great step. But, the exam mode doesn't work for one of my students. She tried it for the Graphic Calculator app of GeoGebra (version 6.0.560.0) on her smartphone. The brand of her smartphone is MEIZU. This smartphone is made in China. She pretend that you can't buy it in Europe. The operating system on her smartphone is Android 5.1.
When she want to start the exam mode, the app asks to switch off wifi and bluetooth and to switch on the flight mode. She carries this out. Everything runs normally up to here. But then, the screen doesn't become green, it stays blue. She can go out of the app without having a red screen. When she click again on 'Exam mode' in the menu, nothing happens. The exam mode doesn't start. There is also no closing screen.
My student thinks that the brand of her smartphone is the cause of this problem. In my opinion that should not be allowed. I thought GeoGebra wanted to conquer the Chinese market.
What is the technical cause? Is there a simple solution for my student?