Reboot the phone. Go to Settings > Biometrics and Security > Fingerprints. You should now be able to register a fingerprint normally. The "Add fingerprint" option must return.
If the above doesn't work, you can run an official diagnostic to see if the hardware is physically broken. samsung fingerprint calibration tool
Utilized in flagship Galaxy S and Note series, ultrasonic sensors emit sound waves that bounce off the ridges and valleys of a fingerprint. This creates a 3D map of the print. Reboot the phone
Click "Start Calibration" on the PC. The phone will emit a high-frequency sound (the ultrasonic pulse) and listen for the return echo from the jig. The software will calculate: If the above doesn't work, you can run
You will see a status bar. If successful, the software will display "PASS – Sensor Calibrated."