Public requests timing out. (private requests resolve, port forwarding verified)

Completely fresh OS (Ubuntu server) and NextCloud install (via snap).

Browser requests to local IP over LAN resolve to web ui. Everything seems to work as it should.
Browser requests to public IP over WAN, when routed to Nextcloud server, time out.

I’ve confirmed that my port forwarding is working. The way I did that was to change the rule in our router to point to another machine, and spooled up Apache on that machine. After doing so, visiting our public IP via KProxy returned the Apache2 Default Page.

Resetting the router rule to once again point to the Nextcloud server IP then results in requests timing out again.

My guess is that I should be looking for the Apache logs, but since is was all installed as part of the snap, can’t seem to find what I’m looking for.

Am I on the right track looking for the Apache logs?
If so, where can those be found for review?
If not, what should I be looking at instead?