For chromecast to work with the app, you need to install the jellyfin app from google play, not fdroid or other store.

Also, yarn is developed by facebook.

So I actually had this exact issue about a month ago.

Solution: You have to connect to chromecast through your phone app. However, the jellyfin app have to be installed through play store. If you install it through f-droid or similar it won’t work.

Took me about a month of troubleshooting to find that answer. :D

Does that include videos?