Unknown client or client not enabled Identity Server 4

Question

I have been getting this error and i have searched for answer online and almost all of them has been talking about requesturis and i have double checked to make sure that my uris are configured properly. I did not find any clue about it. Any thoughts.

Identity Server 4 settings:-

  public static IEnumerable<Client> GetClients()
        {
            return new List<Client>()
            {
                new Client
                {
                    ClientName="KtsWeb App",
                    ClientId="ktswebclient",
                    AllowedGrantTypes= GrantTypes.Hybrid,
                    AccessTokenType = AccessTokenType.Reference,
                    RedirectUris = new List<string>()
                    {
                        "https://localhost:44355/signin-oidc" //Client URL Address

                    },
                    AllowedScopes =
                    {
                        IdentityServerConstants.StandardScopes.OpenId,
                        IdentityServerConstants.StandardScopes.Profile
                    }
                }
            };            
        }

Client settings:-

services.AddAuthentication(options =>
            {
                options.DefaultScheme = "Cookies";
                options.DefaultChallengeScheme = "oidc";
            }).AddCookie("Cookies",
              (options) =>
              {
                  options.AccessDeniedPath = "/Authorization/AccessDenied";
              })
              .AddOpenIdConnect("oidc", options =>
              {
                  options.SignInScheme = "Cookies";
                  options.Authority = "https://localhost:44380"; //Identity Server URL Address
                  options.ClientId = "ktswebclient";
                  options.ResponseType = "code id_token";
                  options.Scope.Add("openid");
                  options.Scope.Add("profile");
                  options.SaveTokens = true;
              });

Answer 1

You should always check the identity server logs it would have given you a clear error message probably unsupported grant type.

You have created a hybrid client but forgot to add the secret.

new Client
            {
                ClientId = "mvc",
                ClientName = "MVC Client",
                AllowedGrantTypes = GrantTypes.Hybrid,

                ClientSecrets =
                {
                    new Secret("secret".Sha256())
                },

                RedirectUris           = { "http://localhost:5002/signin-oidc" },
                PostLogoutRedirectUris = { "http://localhost:5002/signout-callback-oidc" },

                AllowedScopes =
                {
                    IdentityServerConstants.StandardScopes.OpenId,
                    IdentityServerConstants.StandardScopes.Profile,
                    "api1"
                },

                AllowOfflineAccess = true
            }
        };

Your code isnt supplying the secret

        JwtSecurityTokenHandler.DefaultInboundClaimTypeMap.Clear();

        services.AddAuthentication(options =>
            {
                options.DefaultScheme = "Cookies";
                options.DefaultChallengeScheme = "oidc";
            })
            .AddCookie("Cookies")
            .AddOpenIdConnect("oidc", options =>
            {
                options.SignInScheme = "Cookies";

                options.Authority = "http://localhost:5000";
                options.RequireHttpsMetadata = false;

                options.ClientId = "mvc";
                options.ClientSecret = "secret";
                options.ResponseType = "code id_token";

                options.SaveTokens = true;
                options.GetClaimsFromUserInfoEndpoint = true;

                options.Scope.Add("api1");
                options.Scope.Add("offline_access");

                options.ClaimActions.MapJsonKey("website", "website");
            });