Problems with Cloudflare and ShortPixel

Hi!

I´m using Autoptimize to configurate ShortPixel on my website.
https://es.ww.wp.xz.cn/plugins/autoptimize/#reviews

My problem is I´m using Cloudflare CDN and ShortPixel don´t allow that.

I found this instrucctions
https://help.shortpixel.com/article/221-can-i-use-shortpixel-adaptive-images-with-cloudflare

and I added to CloudFlare the CNAME record. But I dont understand where is the step 4. May you help me?

Thanks!

The page I need help with: [log in to see the link]