If the system is unable to find an exact match on Apple Music, it will grey out those buttons. If we have an exact match for Spotify, we will link directly to that song. In cases where we don't have an exact match, the Spotify button will be greyed out.
If there is no song preview and both the Apple Music and Spotify buttons are greyed out, there is a good chance that the song is currently unreleased and not available on streaming services.