IdentityServer4 always returning "error": "invalid_scope"

Question

I'm using IdentityServer4(4.0.4), however it doesn't return the access_token, it always returns: "error": "invalid_scope"

The error can be recreated just by adding the following code and the Nuget packages IdentityServer4(4.0.4) and IdentityServer4.EntityFramework(4.0.4). Adding 'scope' in the request doesn't make any difference.

This is the endpoint being triggered from Postman:

This is my Config class:

using IdentityServer4;
using IdentityServer4.Models;
using System.Collections.Generic;
using System.Linq;

namespace WebApplication1
{
    public class Config
    {
        public static IEnumerable<ApiResource> GetApiResources()
        {
            return new List<ApiResource>
            {
                new ApiResource("ApiName", "ApiDisplayName")
            };
        }

        public static List<IdentityResource> GetIdentityResources()
        {
            return new List<IdentityResource>
            {
                new IdentityResources.OpenId(),
                new IdentityResources.Profile() // <-- usefull
            };
        }

        public static IEnumerable<Client> GetClients()
        {
            return new[]
            {
                // for public api
                new Client
                {
                    ClientId = "secret_client_id",
                    AllowedGrantTypes = GrantTypes.ClientCredentials,
                    ClientSecrets =
                    {
                        new Secret("secret".Sha256())
                    },
                 AllowedScopes =
                {
                    IdentityServerConstants.StandardScopes.OpenId,
                    IdentityServerConstants.StandardScopes.Profile,
                    "ApiName"
                }
            }
        };
    }
}
}

This is my Startup class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace WebApplication1
{
    public class Startup
    {
        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddIdentityServer()
             .AddDeveloperSigningCredential()
             .AddOperationalStore(options =>
             {
                 options.EnableTokenCleanup = true;
                 options.TokenCleanupInterval = 30; // interval in seconds
             })
             .AddInMemoryApiResources(Config.GetApiResources())
             .AddInMemoryClients(Config.GetClients())
             .AddInMemoryIdentityResources(Config.GetIdentityResources());
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseIdentityServer();
            app.UseRouting();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapGet("/", async context =>
                {
                    await context.Response.WriteAsync("Hello World!");
                });
            });
        }
    }
}

Answer 1

You have to add ApiScope in the config. was changed in the latest IdentityServer4 just like this:

        public static IEnumerable<ApiScope> GetApiScopes()
    {
        return new List<ApiScope>
             {
                 new ApiScope(name: "read",   displayName: "Read your data."),
                 new ApiScope(name: "write",  displayName: "Write your data."),
                 new ApiScope(name: "delete", displayName: "Delete your data."),
                 new ApiScope(name: "identityserverapi", displayName: "manage identityserver api endpoints.")
             };
    }