Pi-hole admin page not loading, DNS service not running

[jkaplon]

@Mcat12, thanks for the help.

I'm not sure how I missed it previously, but this appeared in tonight's frantic searching:

Algo/Ubuntu starting dnsmasq

You can, but I think it's a dependency of network manager and it will be installed again on a system (auto) update. I posted this info here: Due to the nature of your environment and the presence of Network Manager, after FTLDNS is installed, you need to make sure that Network Manager does NOT enable dnsmasq (at reboot) before FTLDNS. In order to achieve that, you need to edit /etc/NetworkManager/NetworkManager.conf And comment out or delete the line that has dns=dnsmasq. Then you need …

After trying a bunch of stuff, it was that edit to /etc/NetworkManager/NetworkManager.conf that got everything running again.

On my initial install of pi-hole, I had to remove /etc/dnsmasq.d/network-manager...maybe some recent Ubuntu Mate package updates decided to change up the Network Manager settings again.
I'll certainly think twice before my next apt-get upgrade...