Trying to register my Mesh WiFi and it is a saying the serial number is invalid

[evanwilliams17]

System: WiFi router
Battery or AC: AC
Model: AX6600 Tri band WiFi router
Frequency of occurrence:
Reset OS:
Screenshot or video:
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Detailed description：
having updated firmware the app suggested registering the device I created an account but not able to Register as SN not recognised.
bought in September 2020

[GEEK_ASUS]

Hi @evanwilliams17 ,
Please check your PM.
Thank you.