Certificate does not work on subdomain

Hi,
I am able to activate the SSL for my domain and it works fine
but, it’s not working on cp.domain.com, the error is that the certificate is not valid
I have created an a entry of cp.domain.com
what else can I check? I have tried to disable the cert and add it back with v-add-letsencrypt-domain and works fine, it’s just that it want work on the subdomain
what can I check?
thank you!

if you speaking about the hestia interface: SSL Certificates and Let's Encrypt — Hestia Control Panel documentation