Unable to get closed captions with this code ?

[akhil-nair-1]

var yt = YoutubeExplode();

var trackManifest = await yt.videos.closedCaptions.getManifest('_QdPW8JrYzQ')

var trackInfo = manifest.getByLanguage('en'); // Get english caption.

if (trackInfo != null)
{
// Get the actual closed caption track.
var track = await youtube.videos.closedCaptions.get(trackInfo);

// Get the caption displayed at 1:01
var caption = track.getByTime(Duration(seconds: 61));
var text = caption?.text; // "And the game was afoot."

}