Old personal downloaded music not downloading now on Apple Music

I had this problem a few years ago, but Music that I had on CD that I added to iTunes caused problems in certain cases. For instance, I ripped and downloaded to iTunes all Pat Metheny albums. Now some of them I can add to iTunes and some of them I cannot. I am fairly sure that the problem was with the iTunes library, but I cannot remember how I fixed it in the past. Anybody else have this problem?