Web App working in the browser but not on iPad

I have a web app build on Firebase and it works fine with the desktop browsers.

But it does not work on iPad for some reason (Safari or Chrome). It kind of opens the first screen (shows title only, rest of the screen is white) and the spinner stays on forever.

What could be the reason it works on Macbook browser(s) but not on iPad? The app is using persisted data for login process, could that be related?

Some resources to check before you post:

AppGyver Academy: SAP AppGyver Quick-Start

Troubleshooting FAQ: SAP AppGyver FAQ