I am an Apple Music user in Canada.
Often I'll read a music discussion where the poster offers a playlist of the songs mentioned. When I click on the link Music doesn't like my country code so only offers "Preview" rather than "Play" -- I get it. So I click the box at the bottom and tell Music I'm in Canada and everything is fine EXCEPT I can't find / see / play the playlist.
I search by name of playlist, by name of poster, ... No Luck.
Almost always they also post a Spotify playlist. When I click on it it plays right off.
These are mainstream publications (like New York Times, NPR Music, ...) talking about big mainstream songs.
And I can search the individual songs and Music plays them fine. So it can't be copyright or permissions.
The issue must be in Music's code.
Weird and annoying.