Have you tried removing the screen protector to see if the fingerprint sensor works? If the fingerprint sensor works fine without the screen protector, I recommend finding a different brand that is compatible with the device.
You also can try testing the fingerprint sensor with the screen protector on in safe mode.
Please follow the steps below:
1. Turn the device off.
2. Press and hold the Power key past the model name screen.
3. When "SAMSUNG" appears on the screen, release the Power key.
4. Immediately after releasing the Power key, press and hold the Volume down key.
5. Continue to hold the Volume down key until the device finishes restarting.
6. Safe mode will display in the bottom left corner of the screen.
7. Release the Volume down key when you see Safe Mode.
8. To exit Safe Mode, restart your device.
Let us know how your device responds after performing this step!
I have the same problem and i have tried 2 other brands same thing i have even tried a brand that has a special circle over the fingerprint area so its not as think but still nope and when i take the screen protectors off it starts working.