Reverse proxy - can access via browser but ios app fails

Hi
I can successfully connect to HA via browser from external network using SWAG with authelia mfa.
but using the HA app on iphone (ios 15) fails with:

Error: Message format incorrect: required key not provided @ data[‘redirect_uri’]

I don’t quite understand what the difference could be between the app and a browser…

Hopefully someone can shed some light on it. :slight_smile: