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I have 2 Pi-Hole instances running, and the webpage doesn't work on either one. I entirely uninstalled and reinstalled one instance as well, but that did not help.
Expected Behaviour:
Webpage should load.
Actual Behaviour:
Webpage never loads, and Firefox shows NS_BINDING_ABORTED for each connection attempt in the network logs.
Your debug log shows you want to use dns1.---.internal, but you don't have created the respective DNS records for it, so Pi-hole is only aware of dns1 as the machine's name.
Pi-hole would create those FQDN records automatically, if you'd configured it to do so, and if it would be aware of your local domain.
However, you did neither enable that nor set dns.domain to match your router's domain-name:
No, sorry for the confusion. I did a poor job of explaining it.
I'm running another DNS upstream that receives RFC2136 updates from my DHCP server. That dns1 domain resolves fine for both IPv4 and IPv6. It's a bit weird because of the way it evolved over the years, but the DNS side of things is definitely being resolved fine. That's also why I have PiHole just accepting anything from upstream, including private IPs.
You are right about the domain = "lan" part though. I meant to set it to an empty string to disable it, but forgot to fix that after reinstalling. Regardless, I fixed that part, so that's working well again.
The only thing that just doesn't seem to work is the web server. It's listening on the port, and everything seems okay, but it takes minutes to load, if it does at all. There's definitely a chance that I've messed up some config somewhere that is making it act weird, but I'm just surprised that this is even an issue, because it always worked fine with Lighttpd, and it works fine with other servers too, so I was wondering if anyone with more knowledge of PiHole might have an idea as to what is wrong.
In writing this, I just had another idea though to try making the request from my phone (which is connected over a VPN), and for some reason it works... When I disconnect the VPN and go back to plain wifi, it no longer works. The reason seemingly is that requests that come from the 2 subnets that PiHole has an IP from work, while ones that are routed through my router don't... Which I have no clue why, because again, it worked perfectly with Lighttpd, and with other software. It's very odd.
Obviously, at this point I think it might be out of your purview, so no worries if you have more important help requests to work on. Thank you very much for taking the time anyways!
Are you sure about setting that to empty?
Your debug log also shows domain=---.internal in a custom /etc/dnsmasq.d/00-search-domain.conf.
Pi-hole v6 won't read /etc/dnsmasq.d anymore, unless instructed to do so, see Custom dnsmasq configs not loading, i.e. your system would have used lan with v6 where it had used ---.internal with v5.
As Pi-hole v6 exposes that option, using --config dns.domain is the v6 way to apply that config.
Honestly I had forgotten I had adjusted the dnsmasq config. I removed the DNS domain though because the documentation states that "all queries for this domain are sent exclusively to this server." My upstream DNS can already handle the local domain anyways, so I just let PiHole forward it through like any other. I'm pretty much exclusively using PiHole for its blocking features and UI, as it's incredibly well made!
No, sorry I kind of buried it in text. The more I look into it though, the more I am convinced that I have misconfigured something.
I'm pretty sure the issue was around long before I updated, and something changed during that update that made it show up. I think it's asymmetrical routing caused by my PiHole being multihomed... I don't know if you happen to be an expert on that or something, but if not, thank you so much again for all your time!