What should I do if it shows "The serial number does not exist" when registering the product?

There are two official website to register now.

For the old models, like NT510, NT520Pro, NT630, NT630 Elite, NT650, NT644, NT644 Pro, please download Foxscanner via this official website and then register.http://www.foxwelltech.com/?flag=y

For 2019 New models, like NT530, NT650 Elite, NT630 Plus, NT680, NT680 Pro, please download FoxAssist via this official website and then register. http://www.foxwelltech.us/