Connection issues with my i-phone

I have been playing around with SmartSDR on my phone via the app and have even recently changed internet service providers from T-Mobile to Xfinity just to make the outside connection possible. I configured the ports ( I think properly) but I am still having issues.

Specifically here is what I see:

When I do the initial connection upon opening the app I am offered two choices, one that shows the SmartLink icon (I presume the outside connection accessible via the cellular network) and just below it is the option for connecting via my local network. When running on my local WiFi network (obviously with WiFi enabled on my phone) it really works well. When I choose the SmartLink connection it works as long as I leave my WiFi enabled. If I disable WiFi or move away from my local network the SmartLink connection just loads partially displaying the frequency but no spectrum display or any audio etc.

I have tried this at many many locations and it doesn't matter what the cellular signal strength is it just doesn't really work when trying to do this external SmartLink connection.

I was hoping that I could finally make this useful but I am sort of at my wits end. It just never seems reliable enough to be useful.

Any ideas?

Thanks

Gary