If you are running WordPress on (PHP7 + Maria DB) or (HHVM + Maria DB) and using nginx as the web server, you will get this error. I think this is a bug in the current release.
Till the time iThemes security doesn’t come up with a fix, you can do the following workaround.
1) Open the file /wp-content/plugins/better-wp-security/core/modules/wordpress-tweaks/config-generators.php in any php editor
2) replace line no 101 with the code mentioned in 2nd bracket {//$valid_referers = $this->get_valid_referers( ‘nginx’ );}
3) Restart Nginx and do you are done.
everything works fine after that. When the fix is released you can update it accordingly.
