Subdomain SSL Issue on Cloudflare Partner hosted website (Hostinger)

Greetings,

Thank you for asking.

May I ask if you are referring to the Cloudflare Origin CA certificate or?

What error do you get? Can you share a screenshot of it?

In terms of a sub-domain, is it like sub.domain.com or www.sub.domain.com or even abc.def.domain.com?

In the meantime, may I suggest below articles: