This morning I tried bypassing the the existing Pi-Hole machine which was acting as my DNS resolver here locally, to see if that was causing any troubles. I got this working originally by setting my 192.168.1.2 Raspi as the primary DNS resolver in my router’s DHCP settings, so that every device which connects locally will point to my Raspi for DNS. The two Raspi’s have DHCP reservations for 192.168.1.2 and 192.168.1.4 respectively, so they are essentially static IP’s. To bypass this configuration, I simply changed the DNS resolver in the DHCP packets to now point to my ISP’s primary and secondary DNS servers. After rebooting everything to obtain the new DHCP packets, I ran the Yunohost diagnostics again, but still received the same error …
So, clearly, having Yunohost behind an existing Pi-Hole installation isn’t the source of the problem. I guess I can rule that out. The error is more about external access into my homelab network though, right? I would have thought perhaps disabling CloudFlare might help, but I’m only using CloudFlare currently for the fmds.geek.nz domain name, which hasn’t been connected to my YH installation at all as yet. My YH installation uses the test-fmds.noho.st domain, so it has nothing to do with CloudFlare as yet. I’m stumped.
I may have found the cause of the problem. It seems that my ISP-supplied router might have trouble with IPv6, according to this post on Geekzone.