AX6600 XT8 - Unable to register - web site says "Serial number incorrect" - port forwarding problem

[ZT-9693ff89]

System: AX6600 XT8
Battery or AC: AC
Model: XT8
Frequency of occurrence: constant
Reset OS: Yes - reset to factory settings. Same problem
Screenshot or video:
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Detailed description：I cannot open port 1194 or any other port EXCEPT 8081. I have successfully opened port 8081 and can see it on canyouseeme.com, but no other port definitions are working. Also, I can't register on your web site - I'm told Serial number incorrect
AX6600 XT8 SN L3IAHZ000993 / L3IAHZ000994

[Blake_ASUS]

Hello John,
For register issue, there should be a main SN on the box that represent the whole set.
Please register with that SN instead of individual router.
Thank you.