Klck turns off stock lockscreen, but doesn't turn on kustom lockscreen.

When I try to apply lockscreen klck, I'm tap save icon, then turn on klck... And nothing!.. How to apply it? How to turn it on? Maybe I need to give it more permissions?

Android 8.1, PixelExpirience ROM.

How is it that these posts are 3 years old and there is no response from the developer. This is weak and shows your effort toward making your product the beat it can be is not there