The biggest problem with subscription services like Apple Music, Spotify and others is the unnerving fact that labels make songs available for streaming on a time-limited basis. As a result, some of the tracks you add to Apple Music playlists may no longer be available for streaming, leaving you with no other choice but to purchase them on the iTunes Store.
Starting with iTunes 12.4, there's a new iCloud status of 'No Longer Available' which you can use to create a dynamically updated playlist containing the songs that you added to your Apple Music library that are no longer available for streaming, here's how.