diff --git a/test/integration/auth_webhook_test.go b/test/integration/auth_webhook_test.go
index 0b6a1f555..8b1ed4742 100644
--- a/test/integration/auth_webhook_test.go
+++ b/test/integration/auth_webhook_test.go
@@ -51,6 +51,8 @@ func newAuthServer(t *testing.T) (*httptest.Server, string) {
 		var res types.AuthWebhookResponse
 		if req.Token == token {
 			res.Code = types.CodeOK
+		} else if req.Token == "not allowed token" {
+			res.Code = types.CodePermissionDenied
 		} else {
 			res.Code = types.CodeUnauthenticated
 			res.Message = "invalid token"
@@ -62,22 +64,20 @@ func newAuthServer(t *testing.T) (*httptest.Server, string) {
 }
 
 func newUnavailableAuthServer(t *testing.T, recoveryCnt uint64) *httptest.Server {
-	var retries uint64
+	var requestCount uint64
 	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		_, err := types.NewAuthWebhookRequest(r.Body)
 		assert.NoError(t, err)
 
 		var res types.AuthWebhookResponse
 		res.Code = types.CodeOK
-		if retries < recoveryCnt-1 {
+
+		if requestCount < recoveryCnt {
 			w.WriteHeader(http.StatusServiceUnavailable)
-			retries++
-		} else {
-			retries = 0
 		}
-
 		_, err = res.Write(w)
 		assert.NoError(t, err)
+		requestCount++
 	}))
 }
 
@@ -93,7 +93,7 @@ func TestProjectAuthWebhook(t *testing.T) {
 	project, err := adminCli.CreateProject(context.Background(), "auth-webhook-test")
 	assert.NoError(t, err)
 
-	t.Run("authorization webhook test", func(t *testing.T) {
+	t.Run("successful authorization test", func(t *testing.T) {
 		ctx := context.Background()
 		authServer, token := newAuthServer(t)
 
@@ -121,6 +121,22 @@ func TestProjectAuthWebhook(t *testing.T) {
 
 		doc := document.New(helper.TestDocKey(t))
 		assert.NoError(t, cli.Attach(ctx, doc))
+	})
+
+	t.Run("unauthenticated response test", func(t *testing.T) {
+		ctx := context.Background()
+		authServer, _ := newAuthServer(t)
+
+		// project with authorization webhook
+		project.AuthWebhookURL = authServer.URL
+		_, err := adminCli.UpdateProject(
+			ctx,
+			project.ID.String(),
+			&types.UpdatableProjectFields{
+				AuthWebhookURL: &project.AuthWebhookURL,
+			},
+		)
+		assert.NoError(t, err)
 
 		// client without token
 		cliWithoutToken, err := client.Dial(
@@ -131,6 +147,7 @@ func TestProjectAuthWebhook(t *testing.T) {
 		defer func() { assert.NoError(t, cliWithoutToken.Close()) }()
 		err = cliWithoutToken.Activate(ctx)
 		assert.Equal(t, connect.CodeUnauthenticated, connect.CodeOf(err))
+		assert.Equal(t, connecthelper.CodeOf(auth.ErrUnauthenticated), converter.ErrorCodeOf(err))
 
 		// client with invalid token
 		cliWithInvalidToken, err := client.Dial(
@@ -142,9 +159,38 @@ func TestProjectAuthWebhook(t *testing.T) {
 		defer func() { assert.NoError(t, cliWithInvalidToken.Close()) }()
 		err = cliWithInvalidToken.Activate(ctx)
 		assert.Equal(t, connect.CodeUnauthenticated, connect.CodeOf(err))
+		assert.Equal(t, connecthelper.CodeOf(auth.ErrUnauthenticated), converter.ErrorCodeOf(err))
 	})
 
-	t.Run("Selected method authorization webhook test", func(t *testing.T) {
+	t.Run("permission denied response test", func(t *testing.T) {
+		ctx := context.Background()
+		authServer, _ := newAuthServer(t)
+
+		// project with authorization webhook
+		project.AuthWebhookURL = authServer.URL
+		_, err := adminCli.UpdateProject(
+			ctx,
+			project.ID.String(),
+			&types.UpdatableProjectFields{
+				AuthWebhookURL: &project.AuthWebhookURL,
+			},
+		)
+		assert.NoError(t, err)
+
+		// client with not allowed token
+		cliNotAllowed, err := client.Dial(
+			svr.RPCAddr(),
+			client.WithAPIKey(project.PublicKey),
+			client.WithToken("not allowed token"),
+		)
+		assert.NoError(t, err)
+		defer func() { assert.NoError(t, cliNotAllowed.Close()) }()
+		err = cliNotAllowed.Activate(ctx)
+		assert.Equal(t, connect.CodePermissionDenied, connect.CodeOf(err))
+		assert.Equal(t, connecthelper.CodeOf(auth.ErrPermissionDenied), converter.ErrorCodeOf(err))
+	})
+
+	t.Run("selected method authorization webhook test", func(t *testing.T) {
 		ctx := context.Background()
 		authServer, _ := newAuthServer(t)
 
@@ -186,25 +232,40 @@ func TestProjectAuthWebhook(t *testing.T) {
 	})
 }
 
-func TestAuthWebhook(t *testing.T) {
-	t.Run("authorization webhook that success after retries test", func(t *testing.T) {
+func TestAuthWebhookErrorHandling(t *testing.T) {
+	var recoveryCnt uint64 = 4
+
+	conf := helper.TestConfig()
+	conf.Backend.AuthWebhookMaxRetries = recoveryCnt
+	conf.Backend.AuthWebhookMaxWaitInterval = "1000ms"
+	svr, err := server.New(conf)
+	assert.NoError(t, err)
+	assert.NoError(t, svr.Start())
+	defer func() { assert.NoError(t, svr.Shutdown(true)) }()
+
+	adminCli := helper.CreateAdminCli(t, svr.RPCAddr())
+	defer func() { adminCli.Close() }()
+
+	t.Run("unexpected status code test", func(t *testing.T) {
 		ctx := context.Background()
+		authServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			_, err := types.NewAuthWebhookRequest(r.Body)
+			assert.NoError(t, err)
 
-		var recoveryCnt uint64 = 4
-		authServer := newUnavailableAuthServer(t, recoveryCnt)
+			var res types.AuthWebhookResponse
+			res.Code = types.CodeOK
 
-		conf := helper.TestConfig()
-		conf.Backend.AuthWebhookMaxRetries = recoveryCnt
-		conf.Backend.AuthWebhookMaxWaitInterval = "1000ms"
-		svr, err := server.New(conf)
-		assert.NoError(t, err)
-		assert.NoError(t, svr.Start())
-		defer func() { assert.NoError(t, svr.Shutdown(true)) }()
+			// unexpected status code
+			w.WriteHeader(http.StatusBadRequest)
 
-		adminCli := helper.CreateAdminCli(t, svr.RPCAddr())
-		defer func() { adminCli.Close() }()
-		project, err := adminCli.CreateProject(context.Background(), "success-webhook-after-retries")
+			_, err = res.Write(w)
+			assert.NoError(t, err)
+		}))
+
+		// project with authorization webhook
+		project, err := adminCli.CreateProject(context.Background(), "unexpected-status-code")
 		assert.NoError(t, err)
+
 		project.AuthWebhookURL = authServer.URL
 		_, err = adminCli.UpdateProject(
 			ctx,
@@ -217,35 +278,61 @@ func TestAuthWebhook(t *testing.T) {
 
 		cli, err := client.Dial(
 			svr.RPCAddr(),
-			client.WithToken("token"),
 			client.WithAPIKey(project.PublicKey),
+			client.WithToken("token"),
 		)
 		assert.NoError(t, err)
 		defer func() { assert.NoError(t, cli.Close()) }()
-
 		err = cli.Activate(ctx)
+		assert.Equal(t, connect.CodeUnauthenticated, connect.CodeOf(err))
+		assert.Equal(t, connecthelper.CodeOf(auth.ErrUnexpectedStatusCode), converter.ErrorCodeOf(err))
+	})
+
+	t.Run("unexpected webhook response test", func(t *testing.T) {
+		ctx := context.Background()
+		authServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			_, err := types.NewAuthWebhookRequest(r.Body)
+			assert.NoError(t, err)
+
+			var res types.AuthWebhookResponse
+			// unexpected response code
+			res.Code = 555
+
+			_, err = res.Write(w)
+			assert.NoError(t, err)
+		}))
+
+		// project with authorization webhook
+		project, err := adminCli.CreateProject(context.Background(), "unexpected-response-code")
 		assert.NoError(t, err)
 
-		doc := document.New(helper.TestDocKey(t))
-		err = cli.Attach(ctx, doc)
+		project.AuthWebhookURL = authServer.URL
+		_, err = adminCli.UpdateProject(
+			ctx,
+			project.ID.String(),
+			&types.UpdatableProjectFields{
+				AuthWebhookURL: &project.AuthWebhookURL,
+			},
+		)
+		assert.NoError(t, err)
+
+		cli, err := client.Dial(
+			svr.RPCAddr(),
+			client.WithAPIKey(project.PublicKey),
+			client.WithToken("token"),
+		)
 		assert.NoError(t, err)
+		defer func() { assert.NoError(t, cli.Close()) }()
+		err = cli.Activate(ctx)
+		assert.Equal(t, connect.CodeUnauthenticated, connect.CodeOf(err))
+		assert.Equal(t, connecthelper.CodeOf(auth.ErrUnexpectedResponse), converter.ErrorCodeOf(err))
 	})
 
-	t.Run("authorization webhook that fails after retries test", func(t *testing.T) {
+	t.Run("unavailable authentication server test(timeout)", func(t *testing.T) {
 		ctx := context.Background()
-		authServer := newUnavailableAuthServer(t, 4)
+		authServer := newUnavailableAuthServer(t, recoveryCnt+1)
 
-		conf := helper.TestConfig()
-		conf.Backend.AuthWebhookMaxRetries = 2
-		conf.Backend.AuthWebhookMaxWaitInterval = "1000ms"
-		svr, err := server.New(conf)
-		assert.NoError(t, err)
-		assert.NoError(t, svr.Start())
-		defer func() { assert.NoError(t, svr.Shutdown(true)) }()
-
-		adminCli := helper.CreateAdminCli(t, svr.RPCAddr())
-		defer func() { adminCli.Close() }()
-		project, err := adminCli.CreateProject(context.Background(), "fail-webhook-after-retries")
+		project, err := adminCli.CreateProject(context.Background(), "unavailable-auth-server")
 		assert.NoError(t, err)
 		project.AuthWebhookURL = authServer.URL
 		_, err = adminCli.UpdateProject(
@@ -270,7 +357,41 @@ func TestAuthWebhook(t *testing.T) {
 		assert.Equal(t, connecthelper.CodeOf(auth.ErrWebhookTimeout), converter.ErrorCodeOf(err))
 	})
 
-	t.Run("authorized request cache test", func(t *testing.T) {
+	t.Run("successful authorization after temporarily unavailable server test", func(t *testing.T) {
+		ctx := context.Background()
+		authServer := newUnavailableAuthServer(t, recoveryCnt)
+
+		project, err := adminCli.CreateProject(context.Background(), "success-webhook-after-retries")
+		assert.NoError(t, err)
+		project.AuthWebhookURL = authServer.URL
+		_, err = adminCli.UpdateProject(
+			ctx,
+			project.ID.String(),
+			&types.UpdatableProjectFields{
+				AuthWebhookURL: &project.AuthWebhookURL,
+			},
+		)
+		assert.NoError(t, err)
+
+		cli, err := client.Dial(
+			svr.RPCAddr(),
+			client.WithToken("token"),
+			client.WithAPIKey(project.PublicKey),
+		)
+		assert.NoError(t, err)
+		defer func() { assert.NoError(t, cli.Close()) }()
+
+		err = cli.Activate(ctx)
+		assert.NoError(t, err)
+
+		doc := document.New(helper.TestDocKey(t))
+		err = cli.Attach(ctx, doc)
+		assert.NoError(t, err)
+	})
+}
+
+func TestAuthWebhookCache(t *testing.T) {
+	t.Run("authorized response cache test", func(t *testing.T) {
 		ctx := context.Background()
 		reqCnt := 0
 		authServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -299,7 +420,7 @@ func TestAuthWebhook(t *testing.T) {
 
 		adminCli := helper.CreateAdminCli(t, svr.RPCAddr())
 		defer func() { adminCli.Close() }()
-		project, err := adminCli.CreateProject(context.Background(), "auth-request-cache")
+		project, err := adminCli.CreateProject(context.Background(), "authorized-response-cache")
 		assert.NoError(t, err)
 		project.AuthWebhookURL = authServer.URL
 		_, err = adminCli.UpdateProject(
@@ -348,7 +469,7 @@ func TestAuthWebhook(t *testing.T) {
 		assert.Equal(t, 2, reqCnt)
 	})
 
-	t.Run("unauthorized request cache test", func(t *testing.T) {
+	t.Run("permission denied response cache test", func(t *testing.T) {
 		ctx := context.Background()
 		reqCnt := 0
 		authServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -375,7 +496,7 @@ func TestAuthWebhook(t *testing.T) {
 
 		adminCli := helper.CreateAdminCli(t, svr.RPCAddr())
 		defer func() { adminCli.Close() }()
-		project, err := adminCli.CreateProject(context.Background(), "unauth-request-cache")
+		project, err := adminCli.CreateProject(context.Background(), "permission-denied-cache")
 		assert.NoError(t, err)
 		project.AuthWebhookURL = authServer.URL
 		_, err = adminCli.UpdateProject(
@@ -409,4 +530,66 @@ func TestAuthWebhook(t *testing.T) {
 		}
 		assert.Equal(t, 2, reqCnt)
 	})
+
+	t.Run("other response not cached test", func(t *testing.T) {
+		ctx := context.Background()
+		reqCnt := 0
+		authServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			_, err := types.NewAuthWebhookRequest(r.Body)
+			assert.NoError(t, err)
+
+			var res types.AuthWebhookResponse
+			res.Code = types.CodeUnauthenticated
+
+			_, err = res.Write(w)
+			assert.NoError(t, err)
+
+			reqCnt++
+		}))
+
+		unauthorizedTTL := 1 * time.Second
+		conf := helper.TestConfig()
+		conf.Backend.AuthWebhookCacheUnauthTTL = unauthorizedTTL.String()
+
+		svr, err := server.New(conf)
+		assert.NoError(t, err)
+		assert.NoError(t, svr.Start())
+		defer func() { assert.NoError(t, svr.Shutdown(true)) }()
+
+		adminCli := helper.CreateAdminCli(t, svr.RPCAddr())
+		defer func() { adminCli.Close() }()
+		project, err := adminCli.CreateProject(context.Background(), "other-response-not-cached")
+		assert.NoError(t, err)
+		project.AuthWebhookURL = authServer.URL
+		_, err = adminCli.UpdateProject(
+			ctx,
+			project.ID.String(),
+			&types.UpdatableProjectFields{
+				AuthWebhookURL: &project.AuthWebhookURL,
+			},
+		)
+		assert.NoError(t, err)
+
+		cli, err := client.Dial(
+			svr.RPCAddr(),
+			client.WithToken("token"),
+			client.WithAPIKey(project.PublicKey),
+		)
+		assert.NoError(t, err)
+		defer func() { assert.NoError(t, cli.Close()) }()
+
+		// 01. multiple requests.
+		for i := 0; i < 3; i++ {
+			err = cli.Activate(ctx)
+			assert.Equal(t, connect.CodeUnauthenticated, connect.CodeOf(err))
+		}
+
+		// 02. multiple requests after eviction by ttl.
+		time.Sleep(unauthorizedTTL)
+		for i := 0; i < 3; i++ {
+			err = cli.Activate(ctx)
+			assert.Equal(t, connect.CodeUnauthenticated, connect.CodeOf(err))
+		}
+		assert.Equal(t, 6, reqCnt)
+	})
 }