Jellyfin server is unreachable after upgrading from Cobia to Dragonfish

Jellyfin has been working nicely as a Docker container for a long time, through a series of upgrades.

Since upgrading to Dragonfish-24.04.2.3, the panel shows that it’s running, but neither its web portal nor the smart TV app can reach the server any more.

If I ssh to the TrueNAS host, ss -lnt shows that it’s listening on port 8096, but nmap from another host shows that port as closed. I’d suspect a rogue firewall configuration, but for the fact that TrueNAS doesn’t do firewalling.

So I suspect a Kubernetes-related routing issue, except that I’ve never managed that technology before. Linux sysadmin, some fairly heavy-lifting networking and automation, but not this specific thing.

I’ve tried the obvious things, like rebooting TrueNAS and downgrading/re-upgrading Jellyfin, and disabling/re-enabling “Host Network” on the Edit page, but none of that has helped either.

I’d like to avoid deleting and re-installing the app, as it now contains metadata for several hundred movies and TV shows, though I’ll back up and restore that if it’s the only viable option.

Does this relate to a known issue that I’ve failed to find in here?

Never mind, it’s working now.

I made several config changes which seemed to have no effect at the time, so I don’t even know what the problem or solution was, sadly.