Connection (superloop nbn fttc) dead and not sure if router (asus dsl-ac55u) is kaput.

Superloop FTTC + Asus DSL-AC55U.

I've been using this configuration for a few years now. Today I logged into the router admin added a new port forward. This was a subsequent entry in the existing table. I chose port 7728 at random - if that makes any difference.

Immediately I lost the WAN.

I tried undoing the port forward, but the internet was still dead.

Since then I have rebooted the NCD, changed cables, reset the modem etc all to no avail.

I contacted superloop support and they said everything looks OK on their end. They sent me an email for router setup (but it doesn't quite match my admin screens).

I can't get connection back but I do not know exactly where the fault is.

LAN light on NCD sometimes solid, sometimes flashing.

DSL light on router is fully off.

ChatGPT is giving me irrelevant advice.

Can anyone set me straight here?

https://preview.redd.it/ia80fbufn9td1.png?width=1370&format=png&auto=webp&s=513bb1e797eeac7fe50db143099fbd6f74184f7d

https://preview.redd.it/7c5y0dufn9td1.png?width=996&format=png&auto=webp&s=e32df5cb0a35b3edddbfdb8e1d4c1e9484b3f5fc

https://preview.redd.it/sgsc7eyin9td1.jpg?width=4032&format=pjpg&auto=webp&s=4c267acc981640ce8b1a550039e03c043abc4cf4

https://preview.redd.it/x8qdaeyin9td1.jpg?width=4032&format=pjpg&auto=webp&s=99f979184005f80c6b69fec1fe1d41a69047a027