Albums that show in Apple Music PC app but will not play

I have many music albums, purchased on CDs that I have loaded onto my PC. These played though the iTunes PC app, and until recently, played through the Apple Music app. Now, they appear in the Apple Music app, complete with Album art and song lists including timings – but will not play. I have song sync turned on.

If I delete the album from the Apple Music library, then drag the album from its location on the hard drive into Apple Music they will now play but I have several hundred albums – surely there is a better way to get them back into Apple Music!

Can someone help me out here?