Sony Walkman NWA306 and Apple Music

I have bought a Sony Walkman NWA306 and would like to download music to play offline via Apple Music. I already use Apple Music for ios devices without issue and have a subscription. I can log in and stream music via Apple Music on the Sony Walkman. If i try to download an album then i receive a warning i have too many devices so I have reduced devices via the Apple site (fair enough there were devices no longer used but this does not impact downloading on my iPhone) but continue receiving the same message on the Sony Walkman. I have checked and the Android version and all apps from Google Play are up to date. Apple Support tell me its a Sony issue. Sony Support tell me its a Google Store or Apple issue. I have uninstalled, reinstalled, reformatted and all to no avail so any suggestion would be gratefully received. Thanks