the log stays empty after failing a login even though logging is set to on. the plugin states: Error: Your web server returned 403 Forbidden when checking WSL end-points. This issue usually happen when:
1. Your web host uses mod_security to block requests containing URLs (eg. hosts like HostGator, GoDaddy and The Planet). On this case, you should contact your provider to have WSL end-points urls white-listed.
2. There is a .htaccess file that prevent direct access to the WordPress plugins directory.
In any case, WSL requires this url to be white-listed:http://www.domain.com/wp-content/plugins/wordpress-social-login/hybridauth/