Certain Songs Are Under-intensified in Apple Music

[BeK]

Why are some songs greyed out and some are not? I have never understood this regard Apple Music. The ones that are under-intensified won't play either as I get a error when trying to do so.
Has anyone else experienced this bug?

 

[spitf1r3]

I'm guessing these aren't available in your country (anymore?) due to the licensing restrictions.

Music Tracker lets you track such changes in availability (for the music you add to your library).