Music file copying from Mac to iPhone
Trying to copy music files from Mac iTunes library to iPhone 6, with music previously loaded onto Mac from a flashdrive. Music is purchased from iTunes on another Mac. Problem appears when dragging the music files from Mac library to the synced iPhone. Files don't copy and a message appears that the files don't exist, plus each music filed is then preceded by a circled exclamation symbol? Tried several attempts, with same results.
iPhone 6