Royalty free music

Maybe it worked before, as far as I know, now YouTube blocks not only the soundtrack, but also the video itself and you have to either delete the whole part of the video, or upload the clip again and insert other music. You can use a service with royalty free music. There's a huge amount of music there that you can use in your video. Youtube will not block the audio tracks. I'm telling you from my experience, because I often post different videos on YouTube myself.