This sucks. I posted on reddit. Hopefully some of you all see it. Copying here...
TLDR: try http://forums.applenova.org for now while I (Brad) sort things out.
About six hours ago (2022-06-22 ~0600 EDT), something went wrong with AppleNova.com's DNS. I'm not sure if it expired, but I'll be reaching out to alcimedes soon because he owns the record. I think it's finally time to transfer that ownership...
About an hour ago, I purchased applenova.org, pointed it to the same IP address, and edited all my configs to serve the same content on both host names. It may take some time for the new .org address to propagate DNS everywhere. So, you can now temporarily use http://forums.applenova.org to access the forums. I have not yet set up new SSL certificates; so, your browser will probably give you warning messages if you try https:// URLs. I'll work on that later this evening.
I'll update this post with details if/when I have them.