There is a setting on the XP8 called Adaptive Brightness. When that is turned on, your device will adjust screen brightness on its own based on how much light is hitting the senser under the screen. If you’d like to turn this feature off, follow these steps:

  1. Open Settings.
  2. Click on Display.
  3. Switch Adaptive Brightness off. (the toggle will move to the left and turn grey)

If you need any further assistance with this question, please contact the Sonim Customer Experience Center at 1-833-MY-SONIM (1-833-697-6646) or email us at [email protected]  We are open 24 hours a day, Monday-Friday and we will further assist in troubleshooting.