I have a long standing Apple Music subscription, but I can't listen to an album i purchased on iTunes

Why is my purchase greyed out? Why can't i play tracks that have the small 'Purchased' note on them? Why are their different types of 'purchased' for the songs. I paid for this in iTunes and have also had an Apple Music subscription since it started. I bought this before 2008, so there's no record of this purchase in my iCloud account which only shows records back to 2008. Why can't i even purchase it again if i want to?