Songs added to my Playlist on Mac won't play on my iPhone Music App

SO I WENT on music app on my mac device and im adding my own songs to my library i added a few unreleased songs from a artist i like and then when i go my phone to listen i press play and it just pauses the song nothing plays idk what that is can somone help??? did they not allow use to do it no more... btw when i play it on the mac i can listen not on my phone

[Re-Titled by Moderator]