Page not found connecting using CNAME

Hi, I try to connect by creating CNAME for my subdomain
blog.riselio.com to riselio.netlify.com
but it keeps showing Not Found
I use Cloud flare for my DNS management

My main domain is connecting to condescending-torvalds-a9812f.netlify.com which work fine

blog and main domain have 2 different content that’s why I try to connect it to a subdomain for blog point to different netlify

Any clue?

hi there, did you see this guide already?