DDNS issues with Fibre 1.5Gig

[Beachsled]

Recently I have been having issues with DDNS forwarding on my network. I have the 1.5Gig fibre plan and have the technicolor NAH/modem. It is connected straight to my own router using the NAH in 10G bridge mode. I am getting a proper external ip on my own router, I have everything else working but for some reason can't get my DDNS services to work.

Does anyone have any advice on where to start?

Thanks

[Nighthawk]

Does the external IP you're seeing on your router match what the actual external IP is showing on a site like WhatIsMyIP.com?