How to Put Youtube Video Thumbnail in embed thumbnail?

Question

The problem is in the .setThumbnail method. The image is not loaded in the embed. I always get this: here

const embed = new MessageEmbed()
    .setTitle(song.name)
    .setDescription('Some description here')
    .setColor('#0099ff')
    .setThumbnail(song.url); // <- not working
message.channel.send({ embeds: [embed] });