Problems with connectivity

[Sutton]

I was using Jellyfin on iOS without issues until my server PC's IP address changed. Now, while the new IP works in browsers and on Apple TV via Swiftfin, the Jellyfin Media Player on the host PC and the Jellyfin/Swiftfin apps on iOS can't connect. I get:
"We're unable to connect to the selected server right now..."
No VPN is being used.