Hello @dukeside, welcome to the Let's Encrypt community.
Let’s Encrypt offers Domain Validation (DV) certificates and not certificates for IP Addresses.
Those are IP Addresses and not Domain Names.
Thus you need to own and have control over the Domain Name (or have a subdomain under an existing domain name, for example pointed to your server by your employer or school) you wish to obtain a certificate for, from an ICANN Accredited Registrar.
Please update your Certbot current release is Certbot 2.9.0 Release
See Certbot Instructions | Certbot
Also please see Certificates for localhost - Let's Encrypt