Hey Petra. Try pulling out the battery and replace it afterwards. Power the AG Mobile device back on and observe. If the issue persists, kindly comment below with below with the full model number as seen on the white sticker under the the battery and we will gladly try and assist further. Otherwise, this may be owing to:
- A bad touchscreen - particularly is you can toggle the screen backlight by short pressing the power button.
- Or it could be a corrupted system file - a hard reset will be required most likely to remedy such