Syncing iPhone with iTunes
I am attempting to sync my iPhone with iTunes on my MacBook Pro. I get the error message "The iPhone could not be synced because this computer is no longer authorized for purchased items that are on this phone." It tells me to authorize the computer (Account > Authorzations > Authorize this computer). When I do this I am told the computer is already authorized. I tried de-authorizing and re-authorizating the computer but still get the same error. Both the computer and the phone use the same Apple Id.
How do I get around this? Until I do I cannot free any space on the phone by deleting music.
iPhone 5c, iOS 10.0.2