Try to restore to factory settings.
1. Turn off your Galaxy Note 4.
2. Press and hold Power, Volume Up and the Home button until you see Recovery booting in blue at the top of your screen. Release the buttons.
3. You'll now be in Recovery Mode. Use the volume buttons to scroll up and down and the Power button to confirm. It's not a bad idea to wipe the cache partition while you're here, but it is not essential.
4. Scroll down to Wipe data/Factory reset and press Power to confirm.
5. Scroll down to Yes and press Power to confirm.
6. You'll see a notification in yellow at the bottom of the screen to confirm the reset has been completed. Scroll to Reboot system now and hit Power to confirm.
7. Your Galaxy Note 4 will now reboot. Once it has rebooted, you can restore your apps and data.
Let me know if this helped.