Google WiFi Can't Get Internet Connection w/FIOS

[meck4671]

After seamlessly using Google/Nest Wi-Fi w/FIOS gigabit internet for 3 plus years, yesterday the system stopped working. My Nest Router sees internet coming in, but the network has no connectivity.  I am connected directly to the ONT via ethernet. I have tried restarting/unplugging/factory resetting the router, power cycling the ONT, switching the ethernet cable, all w/no success. A PC connected to the ONT has limited/no internet connection; after resetting the connection via the FIOS app, there is a strong connection on the PC that quickly drops out.  All the lights on the ONT are green, but for whatever reason the Nest router isn't communicating w/it. I have also tried using a Google Wi-Fi puck as a router w/the same result.

I tried hooking up a Netgear Nighthawk AX6AX4300 to the ethernet cable & it is able to see the internet connection & the speeds in are appropriate (nearly a gigabit). However, the router is only broadcasting at top speeds of ~100 mbps right next to the router, which doesn't seem correct. 

I am truly stumped by this. Both routers see the internet connection coming in, but one cannot broadcast at all & the other at reduced speeds. It almost seems the data from the ONT is "encoded" somehow. 

Any help would be greatly appreciated. 

[Cang_Household]

What do you mean by "seeing the Internet coming in?" Are you saying they have the link connection, but no network connection? Can you screenshot the status page?