How to get back original lockscreen

I tried this keylemon software where you can unlock your screen with facial recognition.

I uninstalled it, but now I can't get back to the original unlockscreen with the blurred background, the round avatar and the password input.

Now I get a black screen with a standard OS X modal that requires a username and password.

I'm able to unlock my screen, but I would like to use the normal unlock screen.

I have difficulty finding a topic that addresses the same problem.

Any help would be much appreciated.