Intuit Quickbooks oAuth 2.0

Hello! I am testing a sandbox connection to Intuit's Quickbooks Online. It seems I am missing something. The initial authorization request appears to go through okay, but seems to stop when the redirect uri is called. I believe Intuit explains the process much more clearly than I can:

I looks like the Radzen app is not handling the server response at step four and not exchanging the authorization codes for refresh and access tokens at step five.

Can Radzen support this type of oAuth process?

I don't mind making code tweaks if needed. Thanks!

The Oauth support in Radzen Angular applications support only the implicit grant flow. The one that Quickbooks supports seems to be the authorization code grant (which Radzen does not support in Angular applications).

I have been able to create a connection to Quickbooks Online (QBO) by using Intuit's .NET SDK. I need to sort out a number of details but I'll consider posting the process in this thread when I can.