No me carga el certificado SSL de los subdominios comprados en Namecheap

Greetings, I bought a domain on namecheap, I used it to set up a WP and everything was fine, the problem is when I use a subdomain, there is no way for that subdomain to notify that it has the SSL certificate, when I use a control panel like hestia panel it tells me I have the certificate but the browser notifies me of an unsafe site, it has already happened to me with two domains that I buy at Namecheap, does anyone have any idea how to get out of this problem?