restore error

What kind of failure? Do you see an error message? You can try the information in this support document that deals with problems with updates. If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support

See this support document for an explanation of the update and restore errors. Get help with iOS update and restore errors - Apple Support

This can be a security software issue, but is generally a hardware fault.

Check for hardware issues

Related errors: 1, 3, 11, 12, 13, 14, 16, 20, 21, 23, 26, 27, 28, 29, 34, 35, 36, 37, 40, 1002, 1004, 1011, 1012, 1014, 1667, or 1669.

These errors mean that your device or computer might have a hardware issue that stops the update or restore from completing.

1. Check that your security software and settings aren't blocking your device from communicating with the Apple update server.
2. Then try to restore your iOS device two more times while connected with a cable, computer, and network you know are good.
3. Make sure that your security software and settings are allowing communication between your device and update servers.
4. If you still see the error message when you update or restore, contact Apple support.