Yoast breaks down my website

I have the latest version of wordpress with the latest version of Yoast SEO
I’m using cloudflare (free edition)

I follows the following guide http://www.onlinemediamasters.com/yoast-wordpress-seo-settings/

I clicked on the security tab as this image http://omm.onlinemedia.netdna-cdn.com/wp-content/uploads/2016/11/Security-Tab-Settings.png

All my website is down now.

what should I do?