iPhone 6S fingerprint reader malfunction
After five unsuccessful attempts to match a fingerprint your iPhone will prompt you to enter your passcode. You can also use your passcode to unlock the phone after any failed attempt.
Once you've unlocked it, do as follows:
- Go to Settings
- Swipe up and tap on the Touch ID & Passcode option
- Enter your passcode
- Tap on each fingerprint and tap on Delete Fingerprint
- Once you've deleted them all, go back and use the Add a Fingerprint option to re-add your fingerprints
- Exit Settings