f.lux not working on Samsung Galaxy Tab 4 8.0 SM-T33NU

  • f.lux is not working on my Samsung Galaxy Tab 4 8.0 SM-T330NU. The device has been rooted and f.lux has been granted access. My location is detected correctly. When I toggle "disable flux" on and off, the screen goes black and only comes back if the lock button is pressed twice. Any suggestions why it may not be working?