Error: can't download. Donwloading after few tryes, but huge amount errors when downloading channel! ((

Please, fix error.
If I add channel, all videos parsed, and downloading has sterted, but 90% of all videos - "Can't download". For downloading I need to few times click "download" button. After several errors downloading has began. So strange!
And, in 4K Youtube to mp3 - similar problem.