The main page is on a dual-stacked server, you are using legacy IP and your address is: 18.222.113.226 (ec2-18-222-113-226.us-east-2.compute.amazonaws.com)
The server address you have reached is: 195.30.8.34
You are using SSL, so the literal-address iframes are broken
(because LE is not issueing certificates for IPv4/IPv6 addresses)
and
browsers declare the site insecure (because of the iframes that
have no valid certs).
Use the non-SSL site
to check for NAT64/464XLAT setups (which need literal-address tests)