Google Nest Wifi Pro stopped working with the AT&T BGW Modem/Router

Passthrough is set up on the BGW

DNS entries are blank so can't add the 8.8.8.8 recommended everywhere

I have this problem every couple of months. The Google nest pros stop working with a pulsating yellow light. I used to reset the entire network, reinstall and it would start working again.

But today, I'm able to reinstall the main unit (since the Mac address has been manually entered I guess)

For all additional units, I keep getting the "DNS resolution failed for service: googlehomefoyer-pa.googleapis.com:443" error.

I'm stuck and would really appreciate any help