This feature allows you to set a list of usernames which will ban the IP of the users trying to login with any of these usernames.
NOTE : If the usernames in the list actually exist, then the user will be allowed to login and the Client IP will not be blacklisted.

Creating the Username Auto Blacklist

To create the list of usernames, please go to WordPress Admin Panel -> Loginizer Security -> Security Settings.
There you will find the Username Auto Blacklist Setting section.
Enter the usernames you would like.

The following is a screenshot of the settings page