@matigo The computers I'm testing from don't have IPv6.
I'm certain hub.10centuries.org is NOT being proxied correctly through CloudFlare based on the difference in IPs coming back. Otherwise, I would see exactly the same IP address for as I do for 10centuries.org, which is…different.
In fact, I can connect to http://www.phoneboy.info just fine. It redirects me to the same URL, just https where it fails. And you said you're not running HTTPS because of certificate issues.
Which means I'm fairly certain it's connecting directly to your server at your house and not going through CloudFlare.