Yesterday, Nov 27, 2024, I was manually syncing music from my Music Library on my MacBook to my iPhone and it was working fine. Then my phone said it needed an update, so I let it do that, then music syncing quit. I can find the music in my Library and on my computer in Finder, but when I try to drag it to my connected phone, nothing happens (it used to start syncing and a circle appeared and gradually filled in as the sync progressed, no more...) Its like the phone is not really connected to the computer, but it is in the Devices list....
I also tried the sync function, and I checked that Music knew where my music files were in Finder. Also fails to sync anything.
Apple used to be so reliable, not very much any more.