Stripe is enabled, but a SSL certificate is not detected

I have purchased and setup SSL cert. with Cloudflare on my root and subdomain but the Stripe plugin in WooCommerce in not detecting a SSL.

“Stripe is enabled, but a SSL certificate is not detected. Your checkout may not be secure! Please ensure your server has a valid [SSL certificate]”

The public end of the connection is secure. Which SSL mode are you using in the Cloudflare dashboard? Is it Full (Strict)?