When upgrading from Broadband to Full Fibre. There's a couple of things you'll need to change with how your router is setup.
Unplug the power for your Router and follow the below steps on changing how everything is plugged in.
Note: Your ONT may already have an Ethernet cable into "Port 1" or "LAN". If this is the case, connect the other end of this to "LAN 1" on your FRITZ!Box.
If the above steps don't get you online, please contact our Technical Support team for further assistance.