Just to confirm, have you completed all three steps here? http://www.samsung.com/us/support/troubleshooting/TSG01200322/ If after completing the steps the issue persists, it is recommended to take your phone to a local uBreakiFix location for an evaluation. https://www.samsung.com/us/support/ubreakifix/
Make sure you are registering your fingerprints the way you hold your phone eg..if you are using your thumb and the phone is in your right hand your thumb is not up and down but at an angle
I disabled my Wifi connection so only cellular data was used, and then it worked. I have seen that with several apps that they only seem to work over the cellular service or Wi-Fi service (particularly for Smart home devices). Try that and see if it works.