iTunes does not recognize my iPhone
I'm unable to make a backup of my iPhone 6 to my computer (iMac running OS 10.13.6) because the device does not appear in iTunes (12.8.0.15). I have previously made backups without any problems. My other devices (iPhone 8, iPad air) show up. I've switched USB ports, cables, reset the location and privacy settings on the iPhone and did a hard reset. Any suggestions?