Hi @Phaedrus , thank you for your post in the Flow Community.
I have never used Survey123 before so I was setting up a trial account in order to assist you.
When you are logging to your portal at https://my.company.be/portal what credentials do you use?
If the below doesn't work:
Then I guess for enterprise you need to have the URL prefixed ".maps.arcgis.com"
As you have listed "https://my.company.be/portal", is it possible a URL with ".maps.arcgis.com" exisits and you are just redirecting to it somehow?
Have you asked those who set this up or your IT if they are aware of "Your ArcGIS organization's URL" that is in the ".maps.arcgis.com" format at all?
It defienitly looks like the Oauth requires this format and I wouldn't expect a Flow workaround would be possible with having some sort of custom authorisation process.
So ask around, maybe a URL with the suffix of ".maps.arcgis.com" exisits somewhere.
If you have found my post helpful, please mark thumbs up.
Any other questions, just ask.
Thanks, Alan