OneDrive and ExternalBrowser under iOS

If I would use another option for "Supported account types" I would get the following message:

"unauthorized_client: The client does not exist or is not enabled for consumers. If you are the application developer, configure a new application through the App Registrations in the Azure Portal at"

If you want you can use the following parameters:

Application ID = '9f25ea1e-e5cf-46fa-8e4e-48e938f8e8d4'; 
Client Secret = 'wGUs??]:xFd5OCEZ5YW5U6-a[xBUkiY/'; 

For security reaseons I will delete this application in the Azure portal in a few days.

Thank you for providing the extra information.

Can you please make sure to select "Web" in the "Redirect URI" (Umleitungs-URI) dropdown as indicated in the screenshot here:
I added maybe ten applications in the portal and tried several settings.
And I'm sure that I tried also the standard setting "web". 

After set the 11th app with web = localhost:8000 and the client secret it works now also in your CloudStorageDemo app.

Thanks for your fast support! Now the login and callback is working *thumbsup*

Good to hear it's working now!
Thank you for informing us.