Mistakes made when trying to get LetsEncrypt Certs with IPv6-only domain.
This website now loads on IPv6. Both from the root, https://samcater.com, but also now from https://v6.samcater.com. The second domain only has AAAA IPv6 records, no IPv4 ones. This means free TLS tools like LetsEncrypt will only go for the v6 address.
Getting it to work