Tracks don't work

[Ilya4]

Why can't my friends listen to my added tracks in my playlist, and I can't listen to them on my computer, but I can't on my phone

[PDrew619]

The reason your friends can't hear the songs you add to a playlist from your computer is because they are only accessible to you as they are on your computer.

When you add songs from your personal collection you aren't uploading them to Spotify, you're simply adding your songs just for you to hear using the desktop version of Spotify.