If you are not getting an internet connection at the Nest Wifi but you can directly at the modem, the issue is a setting that has changed with the modem that is preventing it from allowing the traffic to flow through. This is likely due to an update the ISP did. When you switched to a new modem, the issue replicated because the settings the ISP pushed to the new modem during provisioning were the same that caused the original issue.
You need to make sure that the modem is in bridge or passthrough mode (depending on internet service and device) and if it is a modem/router combo, that it is also in modem only mode. You should find the necessary information on how to enable bridge mode from the devices manufacturer's support site.
A trick to try to see if they will auto-negotiate the bridge mode:
- Unplug power from the modem and the Nest router.
- With an Ethernet cable between the modem and router, plug the modem power back in and then immediately the Nest router power cable.
- The modem and router should negotiate the connection and put it into bridge mode.
If the trick doesn't work and you have tried or cannot get the modem into bridge mode or passthrough mode manually, you will need to contact the ISP; it could be a setting they have locked down on their end they'll need to update.
