Ultimate Facebook Fails to Login Users

So I installed Ultimate Facebook and want to allow users to enter with their Facebook account.

I set it up already (or so I think since it does not quite work), but the login with Facebook is not, well, logging people.

When people press the "Login with Facebook", a user is created on the database and I can see the new account with the person profile picture, and the user firstname_lastname. However, it does not login.

Am I missing some step of the configuration? Because it does create accounts, but it does not log people in.

Thanks in advance :smiley:.