I don't want to register my own domain but I want to have an HTTPS connection to my site. Is there a way to do that?
I tried adding SSL to my server using the default subdomain that comes with the server using LetsEncrypt but it said I could not for that subdomain.
Certificates correspond to owned domains, not subdomains. This is because you can prove that you own a domain, but there’s no mechanism to validate you “own” a subdomain.
This provides some of the most important benefits of TLS/SSL, but not all of the benefits of having your own cert. Users can be assured their data is encrypted on route to your site. But if they check the cert, they will see the web host’s information, not yours.
And since the owner of the site will be different than the owner of the domain, you won’t be able to get the ”green bar” that is available only through Extended Validation Certification.
You can create your own certificates that can be used for HTTPS and SSL but the problem is you won't be recognized as an authority for those certificates by any browser. Visitors would need to manually add you as an approved certificate provider into their browser for them to not get security warnings.
This is the purpose of using certs in the first place. A third-party certificate authority is vouching that you are who you say you are in various degrees of assurity. Self-signed certs only say you guarantee you are who you say you are.
The methods for doing this are too long and operating system dependent to go into here. Google for "self signed certificates".
