Why does a YouTube link like this https://youtu.be/qYNCws-a6CQ says that it isn't a valid YouTube ID when I try to add it here https://www.tvmaze.com/externalvideo/create?season_id=119366
Try "https://www.youtube.com/watch?v=qYNCws-a6CQ" or "qYNCws-a6CQ".
What's the reason behind not allowing youtu.be? It's what YouTube uses if you click the Share button.
Done!