Issue for wdmycloud log in

Would like seek help for setting up the personal cloud.

Currently major issue is can’t sign up on which means I can only transfer file within home. 

It always come following error message

The web access account you requested for could not be created. Ensure that you do not have any network connectivity issues and try again. (250006)

I have tried quite a lot methods provided on the forum

enable the upnp mode and port forwarding from my router

try to set network mode from DHCP to static

both can’t work

Is there anything I can do? I use Aztch DSL7002GRV(S) router



Please follow the steps from the user manual on page 60