https://letsencrypt.org/howitworks/technology/#domain-validation https://letsencrypt.org/howitworks/technology/#domain-valida... There's a bit more to it than

https://letsencrypt.org/howitworks/technology/#domain-validation https://letsencrypt.org/howitworks/technology/#domain-valida... There's a bit more to it than "allowing subdomain creation". You will need control over the DNS records, or ability arbitrarily change the page (essentially).