RBK762S disconnected frequently.

I brough ORBI RBK762S 1 weeks ago, router unstable and disconnected frequently even I chat with Netgear apps support, the guy told me reset the router (actually I did it 2 times before). I reset the router and the following 1 day is fine, but problem come back today.

I go for lunch and come back home but lost the wifi signal, after few mins the wifi come back.

when I try to listen music from the server (desktop) to the KEF active speaker, suddenly stop, I saw the router white light blanking.

Anyone dan tell what is going on?

Product :  RBK762S

Router Firmware VersionV6.3.6.4_1.2.68

Thanks

Tom