Troubleshoot iMac Music app not playing

Itunes app on my iMac shows my library but when I click to play a song it quickly scrolls through all the songs on that album and does not play any of them. I re-booted the computer but it still is doing this eratic scrolling. My iTunes on my iPhone 6 is playing fine. I am an Apple Music subscriber. How can I fix this on iMac? Jim OD