I host some services at home myself and so far have only used DNS records and self-signed certificates for them. Now I'm having some issues with self-signed certificates (some apps are not working properly) and am trying to get a public domain to fix these issues. Before I do that, I just want to clear up one question that I have.
If I had my own public domain, let's say example.com and created a local subdomain, let's say plex.example.com. Can I create a Let's Encrypt SSL Certificate for this local subdomain? or should the subdomain also be public?