"Your iPhone has never been backed up to iCloud."
Sent a 7 Plus in for repair and they couldn't repair so they sent me a new one. Now I try to back up to iCloud in iTunes and despite repeated manual attempts to back up it still says "Your iPhone has never been backed up to iCloud." It seems to be backing up, but I get the same message.
It appears to back up fine to "The computer," but I want to also back up to iCloud.
Any ideas?
iPhone 7 Plus, iOS 11.3.1