What phone are you using? It means check your fingerprint recognition sensor issues on your phone such as your fingers are wet, isn't recognised, bending your finger and your fingertip isn't recognised, affected by wrinkles and scars. Do the following such as:
• To improve recognition performance, register fingerprints of the hand used most often to perform tasks on the device • Clean the fingerprint sensor dry • If not. Delete them and register again.
to improve performance you clean an the sensor Update the app called "Lock Screen" make sure itis version 5 and above to work properly Delete all your fingerorints and register again
-if problems persist please counsolt your samsung service center
