Why can't I change my lock screen on my Note 4

[AC Question]

I've been using Note 4 for one year with no issues but 3 days ago I changed my screen lock pin to fingerprint. Everything was okay I used fingerprint for 3 days. Yesterday I wanted to change the lock and make it pin. I did it and I am sure that I enter the pin correctly but when I locked the phone there was none security things I think I was wrong so I open the settings and I saw that I says 'secured with pin' I tried the pin that I use always but it didn't work. Again on the lock screw there is no lock what can I do ?

 

[belodion]

Have you tried Clear Credentials in Settings, Security?