iOS app fails to launch after deploying to iTunes

I am using ionic pro package to create an iOS .ipa file from my project. I have tested it on an emulator on my iOS device and the app runs as expected.
However when I use TestFlight to run the app on my physical device it fails to load properly (looks like ionic isn’t starting up)
How it looks:

How it should look:

I’m mostly just confused as to why it works locally using ionic cordova run ios but when built with package its doing this.

Any help would be greatly appreciated.

I should note, I don’t know how to debug a live app on an iOS device. I can’t use remote devices in chrome and can’t find any JS/webview logs to inspect. So I just have no idea what’s even going wrong.

Any tips for how to debug a deployed application on a physical iPhone? Or even just any insight into what might be going wrong with this packaged version?

Did you ever find a solution? I am getting the same issue. Works on Web, Android Store, works with iOS emulator on iPhone, but not working once published to iTunes App Store. I am thinking it is a permission issue trying to connect using REST (json) calls on iOS which I don’t have the issue on Android.