Hi
It sounds like the portforwarding in the Router is not done correct or the Radio RRC cannot update the ddns server. Can you browse the Radio RRC if you use the routers public IP address ? At the status page in the Radio-RRC you can see if the ddns update is working. Most common reason that it's not working is that the DNS setting is not correct, but it will also be shown on the status page.
73 de mike