"Could not backup your iphone beasue an error occured" is the error message while using my windows computer to backup
"Could not backup your iphone because an error occured" is the error message while using my windows computer to backup my iphone 6
If the link on top of this page under "Related Article" did not help then try these...
Connect iPhone to Computer
Use your USB lightening cable --> Resolve USB-related alerts in iTunes - Apple Support
If unable to connect --> If iTunes doesn't recognize your iPhone, iPad, or iPod - Apple Support
For your Windows PC —> Troubleshooting issues with iTunes for Windows - Apple Community
Use genuine cable --> Identify counterfeit or uncertified Lightning connector accessories ...
See how to --> Sync your iPhone, iPad, or iPod using iTunes on your computer ...
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