Hello,
i’m using a 3rd party API for payments and it needs https.
I’ve put in capacitor.config.json => iosScheme:httpsionic but I’ve the same problem 
It’s not possible to run local assets from https.
You can upload them to a server and run the app code from the server, but then apple could reject your app.
Same problem , I use auth0 (third party atuhentication) in my app quasar withj capacitor , Login ok , Redirect OK , put the call XHR error : XMLHttpRequestProgressEvent error