What does "Valid Certificate; Any valid certificate will be matched" mean in Application Policy?

Hi,

I’m trying to figure out how client certificates can be used with an Application in Zero Trust.

Without any Application configuration, I can access my public hostname from the internet.
If I add an Application and select the Valid Certificate policy option, access to my public hostname stops. I’ve downloaded and installed the client certificate from my domain in Cloudflare. Is that a wrong certificate to use?