Playlist on iMac won't fully transfer to my iPhone

On the Music app on my iMac, I have built playlists of songs that I've purchased through iTunes. I recently subscribed to Apple One and have downloaded songs to that playlist. When I sync my iPhone to my iMac however, only the portion of my playlist of songs that I purchased transfers to my iPhone; the songs that I downloaded through my Apple One subscription do not sync to the playlist on my iPhone. How can I fix this? I have also tried to download song from My Music to my playlist on my iPhone, but this doesn't work either.