If you try to scan a random QR code that is not on the lock, it will not work. 

However, if you scan the correct QR code but it still prompts “Incorrect QR Code”, you can also manually input the smart lock's serial number by tapping the "Input Manually" option on the bottom of the QR code scanning page within the Eufy App under Main Page > Security > Add Device > Scan QR code.

If you still have questions, please contact us for further assistance.