WAN connection issues after firmware update on USG lite-60AX

Hi @LukeArchbold ,

Thank you for reporting this issue.

At this point, we cannot yet determine whether the issue is caused by the firmware, the ONT, or the network cabling. The following checks should help narrow down the cause:

• WAN connection type: Under VLAN 10, is your WAN mode set to DHCP, Static IP, or PPPoE?
• Power-cycle both devices: Please restart the ONT and the router together. Some ONTs retain the previous session state, which can prevent a quick reconnection.
  • Allow ONT negotiation time: Sometimes the ONT takes longer to respond or has not fully synced after a reboot, which can delay the WAN connection. Please wait 3–5 minutes after powering on the ONT before checking the connection status.
• Inspect cabling: Please re-seat or replace the Ethernet cable between the ONT and the router.
• Verify WAN VLAN settings: Please re-check the WAN VLAN configuration to confirm that VLAN 10 is still present after the update and that tagging is configured correctly.

If the issue occurs again, please provide us with the following details so we can assist you further:

1. A simple network topology diagram.
2. Enable Zyxel Support Access by following the FAQ below, and share your Organization and Site name with us:Nebula how to turn on zyxel support access
3. If possible, when the issue occurs, please collect the diagnostic file according to this FAQ and send it to us via private message: How to collect diagnostic file on Security router USG LITE 60AX Local WEB GUI?

The local Web GUI "admin" account password can be found under Site-wide > Configure > Site settings.