Iphone 8 error 4000? would not update
why won't my IPhone 8 update, got error 4000 after waiting 1 hour or so to download
iPhone 8, iOS 15
Question marked as
See this Apple article: If you see an error when you update or restore your iPhone, iPad, or iPod
If you see an error when you update or restore your iPhone, iPad, or iPod - Apple Support (SG)
Connect your device to your computer using an Apple USB cable & try also another USB cable.
Turn your iPhone on and unlock it -> enter the passcode.
Go to Settings -> Display and Brightness -> Auto-Lock set to Never.
Guess you use a Windows PC, if so check the AV & Firewall you use on the PC.
Disable all AV & Firewalls temporarily while you restore & update your apple device.
Turn Off Hotspot.
Turn Off or remove VPN if necessary.