Archer C7 with Sky Fibre not working

I've been using an Archer C7 flashed with OpenWrt configured for use with (non-fibre) Sky broadband and it's worked perfectly.

However recently I switched to Sky Fibre, so I tried connecting the Archer C7 to the newly installed ONT via ethernet instead of the modem I was using before but now there is no internet connection.

I'm very inexperienced with networking but does anyone know if this should just work or is there extra configuration required with fibre internet?

Thanks in advance!


it is best to ask your ISP what is a proper settings/config for this new setup
maybe your old setup was DHCP and new is PPPoE ? or vice versa ...
who knows...