I've had this problem for ages, and today, I fixed it
I think this is the process
1. Set up port fowarding for port 80 (Use TCP not UDP )on the hub first. - select a name <DLink_320L_2014> for example
2. Get the Broadband network IP address, under the TCP/IP Settings on the Advanced Settings/Broadband page
3. sort out your DNS server at www.dlinkddns.com. Make sure it has the Broadband network IP address of as the "New IP Address"
4 Remember the hostname you created <Hostname>.dlinkddns.com
5. Run through the DLink network Management Make sure IPv6 settings are "Auto", in fact, make everything auto under the LAN settings
6. On Dynamic DNS, "enable" :
6a. The server is www.dlinkddns.com
6b. the host name is <Hostname> from 4.
Now, when you click on port forwarding, it should find a Upnp router
7. Back to the Home Hub, and complete the game / application setup port by adding a new game, using the port name from 1.
I think that's it
Good Luck!