IOS Music app suddenly started a pop up about "allowing the device to use apple music"

I have been using apple music for about three months now. My music collection is on a mac and has been synchronised with apple music. I have been using an iphone 11 as a player since then. Today, I added a new CD to my mac, which was duly sync'd with apple music, but ever since then, when I try to play it on the iphone, it says "Allow this device to use Apple Music? This device was previously used with a different Apple ID. To access your subscription, you will need to sync your library with this Apple ID. You will not be able to change..." I can still access apple music from the phone without error, until I try to play the new album... so its just the new album added today that is causing the problem. Any ideas why and how to fix?