Swaggerbuckle with AAD --Error AADSTS500013: Resource identifier is not provided - azure-active-directory

Question

I'm trying to use AzureAD to get a token in swagger and test my .netCore2.1 API with it.(using Swashbuckle.AspNetCore 4.0.1)
To do this I completed the following steps
1. Created a Web API project(asp.net Core2.1)
2. Register an Azure AD (AAD) app for the Web API
3. Updated the Web API project to use Azure AD authentication
4. Register an AAD app for the Swagger web site https://localhost:5001/swagger
5. Granted permissions for the Swagger AAD app to access the Web API AAD app
6. Generated a Client Secret for the Swagger AAD app
7. Enabled OAuth2 implicit flow on the Swagger AAD app
8. Added Swagger to the Web API project
When I authenticate, I am getting the following error.
Error AADSTS500013: Resource identifier is not provided .
When I click authorize
I am getting error AADSTS500013: Resource identifier is not provided.
My WebAPI project's startup.cs file goes here
Please help me understand which resource Identifier I am missing here or how to resolve this error.
Or any pointers on how to use Swaggerbuckle with ASP.NET Core webAPI, especially with AAD authenticated WebAPI ?
UPDATES
I copied my webAPI's APPID URI from azure portal. ie Dashboard>>Microsoft - App registrations>>MY_API_APP>>Settings>>Properties>>App ID URI
But I am still getting the same error when I try to authenticate
Error AADSTS500013: Resource identifier is not provided

Answer 1

Usually resource identifier which uniquely identifies your application. You can easily found your resource Identifier Like below:
When logged into the Azure portal, Azure Active Directory > App Registrations > [App Name] > Settings> Properties, then it's the App ID URI
See the screen shot:
In the orignal OAuth 2.0 specification, there is no resource parameter in the authorization request. It use scope parameter. The authorization and token endpoints allow the client to specify the scope of the access request using the "scope" request parameter.
As document explains, when Azure AD implement the OAuth 2.0(1.0 endpoint), the resource is used to specify the access_token you request for which resource. And the Azure AD will issue the token which the scp based on the permission you config on the portal for the resource.
And in the v2.0 endpoint, the Azure AD also use the scope to support the dynamic permission request. More detail you can have a look here.
Usual Reason for Error
Make sure you have configured below steps accordingly.
Like below:
Application Manifest
Reply URI
Request Endpoint
For V1.0 refer this URI https://login.microsoft.com//oauth2/authorize
For V2.0 refer this URI https://login.microsoft.com//oauth2/v2.0/authorize
Application Consent
Need to confirm your application required resource access permission you could refer here
I believe this step can lead you to sort out your problem.

Answer 2

With Azure AD V1.0 app you need set resource to identify which api you want to access during the authentication&access token requests :
Code flow :
https://learn.microsoft.com/en-us/azure/active-directory/develop/v1-protocols-oauth-code
Implicit flow :
https://learn.microsoft.com/en-us/azure/active-directory/develop/v1-oauth2-implicit-grant-flow
In Swashbuckle.AspNetCore 4.0.1 , you need to config the resource as parameter if you want to get access token for accessing your web api :
app.UseSwaggerUI(options =>
{
options.SwaggerEndpoint("/swagger/v1/swagger.json", "MySite API V1");
options.OAuthClientId("19c73866-562f-482a-bafb-89d9fe9b0aaa");
options.OAuthAppName("Swagger Api Calls");
// add resource
options.OAuthAdditionalQueryStringParams(new Dictionary<string, string>() { { "resource", "f479db30-9b62-431b-98c2-bcaae52203cf" } });
});

Answer 3

For us Nan Yu's response got us one step closer.
We added the resource in the AdditionalQuerystringParams like so:
options.OAuthAdditionalQueryStringParams(new Dictionary<string, string>() { { "resource", "{ResourceIDHere}" } });
We are now able to get passed the Auth step in Swagger, but trying routes out doesn't seem to pass the token to the api called and so we get a 401 Error.

Answer 4

change { "scope", API_AppID_URI} to { "resource", API_AppID_URI}