Let's Encrypt makes free security certificates available for IP addresses
We’re all familiar with the idea of TLS/SSL security certificates that verify the identity of a website and ensure trust and security on the web by confirming that the site you’re visiting is what it says it is.
Usually these relate to the domain name of the site, since that’s how most people gain access, indeed if you type in the underlying IP address instead you’ll often get an error because of the lack of a certificate.