Fingerprint sensor not working on Android?

Ask anyone what’s the quickest way to unlock a phone and the answer will be by using the fingerprint sensor. It literally takes a second to unlock the phone and you can start using it as you want. The scanner adds a pretty sophisticated layer of security since your passwords can be guessed by fingerprints and are less likely to be forged. What if you found that the fingerprint sensor is not working on your Android phone?