how to fix unknown error 3
while phone restoring its got stuck and cannot restore after the error pop out.
Try this:
Resolve iOS update and restore errors
Check for hardware issues
Related errors: 1, 3, 10, 11, 12, 13, 14, 16, 20, 21, 23, 26, 27, 28, 29, 34, 35, 36, 37, 40, 1000, 1002, 1004, 1011, 1012, 1014, 1667, or 1669.
These errors mean that your device or computer may have a hardware issue that's preventing the update or restore from completing.
- Check that your security software and settings aren't preventing your device from communicating with the Apple update server.
- Then try to restore your iOS device two more times while connected with a cable, computer, and network you know are good.
- Confirm that your security software and settings are allowing communication between your device and update servers.
- If you still see the error message when you update or restore, contact Apple support.