iOS app (MyCloud, WD Photos) no connection outside LAN

I have been using a WD My Cloud 4TB HD for some time now without problems but lately, I can not connect to the drive when I am not using my LAN WIFI.

I can see the drive using my public IP address and the port specified in the remote settings but neither the WD MyCloud app or WD Photos app can connect. I know my setup is right. The port is open and, as I mentioned earlier, I can connect with a browser. Just not with the iOS apps.

Any suggestions?

Many thanks

I think the problem is solved.

I had forgotten to set up port forwarding for HTTPS in my router and that is apparently the port the iOS app is using.

Hope it helps others with a similar problem.

Thanks for coming back and sharing your solution with the community.