What port is Mycloud application (IOS, PC, MAC) using to connect to the NAS

WD Software & Mobile Apps My Cloud 3rd Party & Mobile Apps
5

Ok, so you configured port forwarding both in your ROUTER *and* the WD, right?  (Not completely clear from your description.)

See if this gets you anywhere:

http://community.wd.com/t5/WD-My-Cloud/HOW-TO-Troubleshooting-Remote-Connectivity-Issues/m-p/617261#M1130