The device is already associated with an Apple ID
From my laptop I uploaded quite a few tracks onto iCloud Music Library with iTunes and my Apple ID. When I try to play the tracks on iPhone with exact same Apple ID, however I got a pop up error message that says “If you use iTunes Match with your Apple ID, you cannot use iTunes Match, auto-downloaded or download past purchases with a different Apple ID for 90 days.” It has me either Cancel or Transfer.