If something has gone wrong, for whatever reason, and you can't login because of the login cooldown, you can remove the cooldown by deleting a particular file.

  1. The file to delete is found within the plugin directory. This will likely be ....wp-content/plugins/wp-simple-firewall/
  2. The file name is mode.login_throttled
  3. Delete this file.

For more information about Login Cooldown feature, read the article here.