Forget it. My problem was a firewall setting in my server. I was disallowing all requests coming from my external IP! What a waste of time! (╯°□°）╯︵ ┻━┻ ¯\_(ツ)_/¯

I run Pi-Hole and a number of other servers on a computer in my home. However, I recently decided to go back to the dhcp server on my router and use Pi-Hole only for DNS. Now, though, it seems like...