IdentityServer4.Templates | dotnet new templates for IdentityServer4 | Identity Management library

I created an empty asp.net core web application (dotnet new web -n ) and went to the github for IdentityServer4.Quickstart.UI and was followed the instructions to add the quickstart UI. I first did the powershell cmd iex ((New-Object System.Net.WebClient).DownloadString('https://raw.githubusercontent.com/IdentityServer/IdentityServer4.Quickstart.UI/main/getmain.ps1')) to download the files and run the application but it keeps telling me Index not found but the file is inside of the Views folder. So I then deleted all those files it downloaded from the project and installed it using its templates by running the cmds dotnet new -i identityserver4.templates then dotnet new is4ui --force which downloaded those files again onto my project. However, it keeps telling me the same message.

I noticed that under the Quickstart folder, contains a folder named Home which has the HomeController.cs and the namespace is as IdentityServerHost.Quickstart.UI... do I need to change that namespace to match my solution i.e. ids.Quickstart.Home?

What is causing this to display that error when infact there is the Index.cshtml file inside of the Views folder?**

This is my startup.cs file:

I using ASP.Net Core 3 Identity with Identity Server 4 for authentication ...

On the AspNetIdentity template the External Authentication Controller Callback method calls the AutoProvisionUserAsync method which has the following code:

Any word on when updates will be available for IdentityServer4's QuickStart examples? Upgraded to V4 from 3.1 today, but there are breaking changes I can't find documentation for. Tried to update the templates:

Background

I'm quite new to Umbraco but have been trying to use IdentityServer4 for the BackOffice of Umbraco. For the IDP, I've used the in-memory configuration (is4inmem template) found here.

For Umbraco I've used the UmbracoIdentityExtensions to configure OpenId Connect.

I've been mainly following this tutorial (this is however, for Umbraco 7).

The problem

I do have the 'Sign in with OpenId connect' button which I configured, but when I try to log in using the IDP, Umbraco does not log me in. I keep getting returned to the login page. Whenever I go to the IDP page, however, I am logged in and can see I've given access as seen in the picture below.

Whenever I log in with an Umbraco account, and then try to 'Link your OpenId Connect account', it does nothing, but upon logging out an error message appears in the screen: 'An error occurred, could not get external login info' I've tried to use different configuration settings, but without success.

Code

IDP Config.cs