First thing is to find out why.
If you live in the USA your fingerprint sensor does not work due to software limitations.
- Clean the sensor
- Try Safe Mode
- Push on/off button
- In menu tap and hold Power Off
- A menu will appear that offers you the choice to reboot in safe mode
- Call Service *#*#SERVICE#*#* or *#*#7378423#*#*
- goto service tests, scroll down and you will see Fingerprint Test
- It should display a Sensor OK
If Sensor not OK contact Support.
