We have seen a lot of this after:-
You cannot access the ether ports...
Solution we use is to set the pc lan address to 192.168.88.x to access the router ether1 on 192.168.88.1
Works for us..
You can also try manually typing in the mac address of the ether1 port - might mean dismounting the board from it's mountings if you did not stick the duplicate sticker with the routers mac addresses into the box.. good practice!!