Casting from Jellyfin will not work

No servers are found

Looking for servers relies on a broadcast, which plenty of networks do not carry: guest and business networks often separate clients from each other, and a server on another network or behind a VPN cannot be found this way. A firewall may also have refused TinePlayer the first time it looked.

Press Enter Address and type it instead, as you would into a browser: http://jellyfin.local:8096. Nothing about casting afterwards depends on discovery having worked.

The code is refused, or none appears

Connecting uses Jellyfin's Quick Connect, which a server's administrator can turn off. Ask for it to be turned on, in the Jellyfin dashboard under General.

The code has to be entered in a Jellyfin client or website you are already signed in to, from the user menu.

TinePlayer is not listed as a player

TinePlayer appears as a player only while it is running and connected. Start it, and TinePlayer should show its Jellyfin connection status on the main screen.

A soundtrack is missing from a cast video

If it is an external audio file beside the video is not listed when casting. See Video, soundtracks and subtitles.

The app's volume changes both outputs

It is meant to. Jellyfin sends one volume, so it moves the All Outputs level and keeps the balance between your two. To change one output on its own, use the volume panel on TinePlayer's playback controls.