IdentityServer4 and ASP.NET Core 2.2 Integrating with ASP.NET Identity

Getting this error

InvalidOperationException: No service for type 'Microsoft.AspNetCore.Identity.UserManager`1[Microsoft.AspNetCore.Identity.IdentityUser]' has been registered.

I am trying to get identityserver and asp.net identity ui to be in one project.

Followed this http://docs.identityserver.io/en/dev/quickstarts/6_aspnet_identity.html#new-project-for-asp-net-identity article to get the needed extra code. I did the following steps

1. Create a ASP.NET Core 2.2 MVC App, Single Account authentication

2. Tested it to make sure it works, registered a user, logged in, all works well.

3. Added nuget package IdentityServer4.AspnetIdentity

4. Added Config.cs file below

   public static class Config
   {
   public static IEnumerable<IdentityResource> GetIdentityResources()
   {
       return new List<IdentityResource>
       {
           new IdentityResources.OpenId(),
           new IdentityResources.Profile(),
           new IdentityResources.Email(),
       };
   }
   public static IEnumerable<ApiResource> GetApiResources()
   {
       return new List<ApiResource>
       {
           new ApiResource("eventsapi", "Events Api")
       };
   }
   public static IEnumerable<Client> GetClients()
   {
       return new List<Client>
       {
           new Client
           {
               ClientId = "client",
   
               // no interactive user, use the clientid/secret for authentication
               AllowedGrantTypes = GrantTypes.ClientCredentials,
   
               // secret for authentication
               ClientSecrets =
               {
                   new Secret("secret".Sha256())
               },
   
               // scopes that client has access to
               AllowedScopes = { "eventsapi" }
           }
       };
   }
   }
   

5. Added ApplicationUser.cs

   public class ApplicationUser:IdentityUser
   {
   }
   

6. Modified Startup.cs (commented code is the generated)

     public class Startup
      {
        public Startup(IConfiguration configuration)
      {
         Configuration = configuration;
      }
   
   public IConfiguration Configuration { get; }
   
   
   public void ConfigureServices(IServiceCollection services)
   {
       services.Configure<CookiePolicyOptions>(options =>
       {
   
           options.CheckConsentNeeded = context => true;
           options.MinimumSameSitePolicy = SameSiteMode.None;
       });
   
       services.AddDbContext<ApplicationDbContext>(options =>
           options.UseSqlServer(
               Configuration.GetConnectionString("DefaultConnection")));
       /*
       services.AddDefaultIdentity<IdentityUser>()
           .AddDefaultUI(UIFramework.Bootstrap4)
           .AddEntityFrameworkStores<ApplicationDbContext>();
       */
       //REPLACED ABOVE
       services.AddIdentity<ApplicationUser, IdentityRole>()
           .AddEntityFrameworkStores<ApplicationDbContext>()
           .AddDefaultTokenProviders();
   
   
   
   
       services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
   
       //ADDDED
       services.AddIdentityServer()
           .AddDeveloperSigningCredential()
           .AddInMemoryPersistedGrants()
           .AddInMemoryIdentityResources(Config.GetIdentityResources())
           .AddInMemoryApiResources(Config.GetApiResources())
           .AddInMemoryClients(Config.GetClients())
           .AddAspNetIdentity<ApplicationUser>();
   
   }
   
   
   public void Configure(IApplicationBuilder app, IHostingEnvironment env)
   {
       if (env.IsDevelopment())
       {
           app.UseDeveloperExceptionPage();
           app.UseDatabaseErrorPage();
       }
       else
       {
           app.UseExceptionHandler("/Home/Error");
            app.UseHsts();
       }
   
       app.UseHttpsRedirection();
       app.UseStaticFiles();
       app.UseCookiePolicy();
   
       //app.UseAuthentication();
       //REPLACED ABOVE
       app.UseIdentityServer();
       app.UseMvc(routes =>
       {
           routes.MapRoute(
               name: "default",
               template: "{controller=Home}/{action=Index}/{id?}");
       });
   }
   

   }