OS5 cell data and WiFi

Before updating to OS5 I had zero problems using the older OS3 version. But I’m now having problems connecting to mycload using the iPhone app.
If I’m connected to my WIFI at home and try to connect to mycloud via the app I just get the spinning loading icon. But if I turn off WIFI on my phone and use my mobile date it shows the drive content almost instantly.
Never expected this problem using IOS3. So why won’t it work on my WiFi. Have not changed any WiFi settings on my router.
Maybe you can tell me how to trouble shoot this glitch.

My Cloud OS3 and OS5 use different ports and connection to different servers.
The following article will help.

29956 My Cloud OS 5: Troubleshooting My Cloud Name Resolution and Routing Issues

Can you explain maybe what I need to do because reading the information in the link did not make any sense to me.