Hello,
We are playing M3U8(HLS) stream on app with .vtt subtitle configuration in ExoPlayer and it's work fine on Android Mobile showing subtitles , But when we connect to Chromecast first and directly play content on Chromecast Device(Android TV) M3U8(HLS) stream playing fine but .vtt subtitle configuration is not working even though we follow official Google Doc where it show how to pass subtitle configuration on Chromecast device(Android TV) :- https://developers.google.com/cast/docs/android_sender/media_tracks
But it's not working and subtitle is not showing on Chromecast Device(Android TV).

Note:- we are using Default Media Receiver in this case not the Custom Media Receiver.

Please let us know what needs to be done here in order to make subtitle works on Chromecast Device also.