Are you sure you have really lauch successfully,please login DYNDNS official web site qu test your account.

and when you launch success,why should IP need update? the function means router's wan ip binding with DynDns-Domain,isn't it?

I do have an active account with Dyn dns, worked perfectly with my previous router with dd-wrt.

IP needs to be updated because my ISP changes the IP every 12 hourse.

On my router, I check it later than one week after registration, same problem.
Then I test it: click the "Login"-Button,
get first an error message " Password incorrect",
wait some seconds,
after the router try it automatically again, the status change to " Succeeded!". No error again.

I do nothing else, only click the button "login" manually.