Orbi WiFi 6 Cable Modem Router / CBR750 - Blinking Downlink Light

I recently purchased an Orbi CBR750 Cable modem / Router.

It installed ok it seems, and the ISP says they see it on their system and everything should be good.  However,  the downlink light (second from left) is continually blinking and the internet light cycles on and off every 90 seconds or so, as the modem seems to continually resetting itself.

I have no idea what to do, but this is untenable, especially becuase I am working from home now like many others..  Paid $400 + for this modem.

The leased modem that I am giving back to my ISP (an Arris DG470P) - gave me no such issue, and was working fine up until the time I disconnected it to install the Orbi.

I have looked everywhere on the internet for a solution,  and the best I could find was that I needed to call my ISP because there might be "noise" on the inbound cable line to the modem, and I should call my ISP to have a service tech come check it out.

Any suggestions???