iPhone 8 activation issue after resetting settings

1. Turn on and set up iPhone.
2. Wake and unlock.
3. Set up cellular service.
4. Use Dual SIM.
5. Connect to the internet.
6. Apple ID and iCloud. Sign in with Apple ID. Use iCloud. Subscribe to iCloud+
7. Find settings.
8. Set up mail, contacts, and calendar accounts.

More items...

Turn on and set up iPhone - Apple Support (IN)

Please look at this --> If you can't activate your iPhone - Apple Support

Carrier Lock:- Request your iPhone’s original Carrier to unlock your iPhone and if they agree and do it, then you may know the further process here --> How to unlock your iPhone for use with a different carrier ...

If you are the owner or the owner has shared all information with you then, in order to open the Activation Lock:- read here --> Turn off Activation Lock - Apple Support Activation Lock for iPhone, iPad, and iPod touch - Apple Support

If you have an unknown Apple ID on the App Store and Apple ID page. (See the pic below)

Learn how to remove a device from a previous owner's account.

If you are not the owner and do not have the Apple ID and Password then there is no way that you can get into this iPhone unless the original owner shares the Apple ID and password with you. If you are lucky you can get into this iPhone if they (owner) accidentally remove the device from their Apple ID.

Return it to your “friend” and get your money back.

You’ve been ripped off.

I agree with Kilted Tim. Try to return the item and get your money back. If that’s not possible, contact Apple Support for further assistance. If you’re in the US please call 1-800-MY-APPLE or outside the US, consult the support articles below.

Contact Apple for support and service - Apple Support

The iPhone is from Australia. How did you come by the device? In my experience, an unknown device is usually associated with a managed device.

What says it's an unknown device? There's not enough information here to know what's going on.