Galaxy S6 edge- why doesn't my fingerprint scanner scan my whole thumb

[Baretrap]

So i was trying to get in my phone and ive noticed that i have to scan my finger like 5 times over and over again to grt into my phone. So i deleted the older fingerprints and tried adding new fingerprints but the % stays at 0% and it only scans like partly of the thumb like just a small smudge in the middle

 

[Elfyn1]

When you register your fingerprints you have to place and hold your fingertip on the sensor then lift it off. Follow the instructions at the bottom of the screen. You have to place and lift your fingertip on and off the sensor several times until the circle around the print reaches 100%. It helps to kind of roll your fingertip back and forth (don't swipe). You can add up to 4 fingerprints.

 

[valorian]

In addition to what Elfyn1 said, make sure you are not sliding your finger.