Problem with Youtube Extractor with C #

Good morning

I'm trying to make an application with WindowsForm in C # to download YouTube audios . I use a Nuget package called YoutubeExtractor .

The code is as follows:

private bool DescargarAudio()
        {
            bool vf = false;
            try
            {
                VideoInfo video = videoInfos.Where(info => info.CanExtractAudio).FirstOrDefault();//OrderByDescending(info => info.AudioBitrate)
                if (video.RequiresDecryption)
                {
                    DownloadUrlResolver.DecryptDownloadUrl(video);
                }
                var audioDownloader = new AudioDownloader(video, Application.StartupPath+video.Title + video.AudioExtension,320);
                audioDownloader.Execute();
                vf = true;
            }
            catch (Exception ex)
            {
                exception = ex.Message;
            }
            return vf;
        }

The problem is that this line returns null :

VideoInfo video = videoInfos.Where(info => info.CanExtractAudio).FirstOrDefault();//OrderByDescending(info => info.AudioBitrate)

And I should return an item from the list. I tried several links and it always gives me the same. I do not know if it could be a problem with the dll or I'm doing something wrong.

Do you have a solution or is there some other package to do the same?

Greetings to all.

Happy Holidays.