SOLVED: Access via local domain works in browser but not app

[mari]

So I have jellyfin running on my TrueNAS's Docker. Works great, via IP:Port. I set up local domains such as jellyfin.local, put them in my local DNS server, and pointing them to a local instance of caddy which is reverse proxying to the internal jellyfin IP:Port, and adding it's own self-signed cert.

It works great in the browser (after accepting the self-signed cert), but the jellyfin media player app, both on the same computer as well as on my smart TV, cannot connect to the server via https://jellyfin.local. I also confirmed via my pihole log that the jellyfin app is sending it's requests to the pihole, so it shouldn't be a DNS issue.

I thought perhaps the app doesn't accept the self-signed certs, so I got caddy to serve jellyfin.local via http, but still the app will not recognize the server on https://jellyfin.local either (which again works in my browser, after a few tries of stopping the browser from auto-redirecting to https).

I also tried adding my caddy local IP to "known proxies" in jellyfin networking settings, as well as adding all=http://jellyfin.local or all=https://jellyfin.local to the "published server URIs". No success.

I have done some debugging and narrowed down to the following:
- The app is hitting the correct DNS, and the DNS is returning the IP of the caddy proxy.
- The caddy logs do NOT show any hits when trying via the app. The logs do show when I successfully connect via the browser.

Any ideas what I need to do to get the jellyfin app to recognize my local domain?