diff --git a/frontend/src/pages/authorize-page.tsx b/frontend/src/pages/authorize-page.tsx
index ede9a24..eac8929 100644
--- a/frontend/src/pages/authorize-page.tsx
+++ b/frontend/src/pages/authorize-page.tsx
@@ -10,7 +10,7 @@ import {
   CardFooter,
   CardContent,
 } from "@/components/ui/card";
-import { getOidcClientInfoScehma } from "@/schemas/oidc-schemas";
+import { getOidcClientInfoSchema } from "@/schemas/oidc-schemas";
 import { Button } from "@/components/ui/button";
 import axios from "axios";
 import { toast } from "sonner";
@@ -73,13 +73,13 @@ export const AuthorizePage = () => {
     isOidc,
     compiled: compiledOIDCParams,
   } = useOIDCParams(searchParams);
-  const scopes = props.scope.split(" ");
+  const scopes = props.scope ? props.scope.split(" ").filter(Boolean) : [];
 
   const getClientInfo = useQuery({
     queryKey: ["client", props.client_id],
     queryFn: async () => {
       const res = await fetch(`/api/oidc/clients/${props.client_id}`);
-      const data = await getOidcClientInfoScehma.parseAsync(await res.json());
+      const data = await getOidcClientInfoSchema.parseAsync(await res.json());
       return data;
     },
     enabled: isOidc,
diff --git a/frontend/src/pages/login-page.tsx b/frontend/src/pages/login-page.tsx
index c93b5e5..92a5656 100644
--- a/frontend/src/pages/login-page.tsx
+++ b/frontend/src/pages/login-page.tsx
@@ -149,6 +149,10 @@ export const LoginPage = () => {
     [],
   );
 
+  if (isLoggedIn && isOidc) {
+    return <Navigate to={`/authorize?${compiledOIDCParams}`} replace />;
+  }
+
   if (isLoggedIn && props.redirect_uri !== "") {
     return (
       <Navigate
diff --git a/frontend/src/schemas/oidc-schemas.ts b/frontend/src/schemas/oidc-schemas.ts
index 853745c..022bdfb 100644
--- a/frontend/src/schemas/oidc-schemas.ts
+++ b/frontend/src/schemas/oidc-schemas.ts
@@ -1,5 +1,5 @@
 import { z } from "zod";
 
-export const getOidcClientInfoScehma = z.object({
+export const getOidcClientInfoSchema = z.object({
   name: z.string(),
 });
diff --git a/internal/controller/oidc_controller.go b/internal/controller/oidc_controller.go
index 185d1af..1bfd932 100644
--- a/internal/controller/oidc_controller.go
+++ b/internal/controller/oidc_controller.go
@@ -273,7 +273,7 @@ func (controller *OIDCController) Token(c *gin.Context) {
 
 		tokenResponse = tokenRes
 	case "refresh_token":
-		tokenRes, err := controller.oidc.RefreshAccessToken(c, req.RefreshToken)
+		tokenRes, err := controller.oidc.RefreshAccessToken(c, req.RefreshToken, rclientId)
 
 		if err != nil {
 			if errors.Is(err, service.ErrTokenExpired) {
@@ -284,6 +284,14 @@ func (controller *OIDCController) Token(c *gin.Context) {
 				return
 			}
 
+			if errors.Is(err, service.ErrInvalidClient) {
+				tlog.App.Error().Err(err).Msg("Invalid client")
+				c.JSON(401, gin.H{
+					"error": "invalid_grant",
+				})
+				return
+			}
+
 			tlog.App.Error().Err(err).Msg("Failed to refresh access token")
 			c.JSON(400, gin.H{
 				"error": "server_error",
diff --git a/internal/controller/oidc_controller_test.go b/internal/controller/oidc_controller_test.go
index b33391b..e6910a5 100644
--- a/internal/controller/oidc_controller_test.go
+++ b/internal/controller/oidc_controller_test.go
@@ -176,6 +176,8 @@ func TestOIDCController(t *testing.T) {
 
 	req, err = http.NewRequest("POST", "/api/oidc/token", strings.NewReader(params.Encode()))
 
+	assert.NilError(t, err)
+
 	req.Header.Set("content-type", "application/x-www-form-urlencoded")
 	req.SetBasicAuth("some-client-id", "some-client-secret")
 
diff --git a/internal/service/oidc_service.go b/internal/service/oidc_service.go
index d75a551..d4a19bc 100644
--- a/internal/service/oidc_service.go
+++ b/internal/service/oidc_service.go
@@ -37,6 +37,7 @@ var (
 	ErrCodeNotFound  = errors.New("code_not_found")
 	ErrTokenNotFound = errors.New("token_not_found")
 	ErrTokenExpired  = errors.New("token_expired")
+	ErrInvalidClient = errors.New("invalid_client")
 )
 
 type ClaimSet struct {
@@ -212,7 +213,7 @@ func (service *OIDCService) Init() error {
 }
 
 func (service *OIDCService) GetIssuer() string {
-	return service.config.Issuer
+	return service.issuer
 }
 
 func (service *OIDCService) GetClient(id string) (config.OIDCClientConfig, bool) {
@@ -424,7 +425,7 @@ func (service *OIDCService) GenerateAccessToken(c *gin.Context, client config.OI
 	return tokenResponse, nil
 }
 
-func (service *OIDCService) RefreshAccessToken(c *gin.Context, refreshToken string) (TokenResponse, error) {
+func (service *OIDCService) RefreshAccessToken(c *gin.Context, refreshToken string, reqClientId string) (TokenResponse, error) {
 	entry, err := service.queries.GetOidcTokenByRefreshToken(c, service.Hash(refreshToken))
 
 	if err != nil {
@@ -438,6 +439,11 @@ func (service *OIDCService) RefreshAccessToken(c *gin.Context, refreshToken stri
 		return TokenResponse{}, ErrTokenExpired
 	}
 
+	// Ensure the client ID in the request matches the client ID in the token
+	if entry.ClientID != reqClientId {
+		return TokenResponse{}, ErrInvalidClient
+	}
+
 	idToken, err := service.generateIDToken(config.OIDCClientConfig{
 		ClientID: entry.ClientID,
 	}, entry.Sub)