diff --git a/frontend/components/auth/auth-sync.tsx b/frontend/components/auth/auth-sync.tsx
index e363eb9..194e74b 100644
--- a/frontend/components/auth/auth-sync.tsx
+++ b/frontend/components/auth/auth-sync.tsx
@@ -3,6 +3,7 @@
 import { useSession, signOut } from 'next-auth/react';
 import { useEffect } from 'react';
 import { useAuthStore } from '@/lib/stores/auth-store';
+import { clearAuthTokenCache } from '@/lib/api/client';
 
 export function AuthSync() {
   const { data: session, status } = useSession();
@@ -10,6 +11,7 @@ export function AuthSync() {
 
   useEffect(() => {
     if (session?.error === 'RefreshAccessTokenError') {
+      clearAuthTokenCache(); // Clear cached token on auth error
       signOut({ callbackUrl: '/login' });
     } else if (status === 'authenticated' && session?.user) {
       // Map NextAuth session to AuthStore user
@@ -40,6 +42,7 @@ export function AuthSync() {
         (session as { accessToken?: string }).accessToken || ''
       );
     } else if (status === 'unauthenticated') {
+      clearAuthTokenCache(); // Clear cached token on logout
       logout();
     }
   }, [session, status, setAuth, logout]);
diff --git a/frontend/components/correspondences/detail.tsx b/frontend/components/correspondences/detail.tsx
index 23ebb13..aa36561 100644
--- a/frontend/components/correspondences/detail.tsx
+++ b/frontend/components/correspondences/detail.tsx
@@ -25,15 +25,6 @@ interface CorrespondenceDetailProps {
   selectedRevisionId?: string;
 }
 
-const normalizeUuid = (value?: string): string | undefined => {
-  if (typeof value !== 'string') {
-    return undefined;
-  }
-
-  const normalized = value.trim().toLowerCase();
-  return normalized.length > 0 ? normalized : undefined;
-};
-
 const normalizeRecipientType = (value?: string): string | undefined => {
   if (typeof value !== 'string') {
     return undefined;
@@ -54,9 +45,9 @@ export function CorrespondenceDetail({ data, selectedRevisionId }: Correspondenc
 
   if (!data) return <div>No data found</div>;
 
-  const normalizedSelectedRevisionId = normalizeUuid(selectedRevisionId);
-  const selectedRevision = normalizedSelectedRevisionId
-    ? data.revisions?.find((r) => normalizeUuid(r.publicId) === normalizedSelectedRevisionId)
+  // เลือก revision ตาม selectedRevisionId ถ้ามี ถ้าไม่มีใช้ revision ปัจจุบัน
+  const selectedRevision = selectedRevisionId
+    ? data.revisions?.find((r) => r.publicId === selectedRevisionId)
     : undefined;
   const currentRevision = selectedRevision || data.revisions?.find((r) => r.isCurrent) || data.revisions?.[0];
   const subject = currentRevision?.subject || '-';
diff --git a/frontend/lib/api/client.ts b/frontend/lib/api/client.ts
index 9d9d88f..964612a 100644
--- a/frontend/lib/api/client.ts
+++ b/frontend/lib/api/client.ts
@@ -5,6 +5,49 @@ import { v4 as uuidv4 } from 'uuid';
 // อ่านค่า Base URL จาก Environment Variable
 const baseURL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:3001/api';
 
+// Token cache for API calls outside React components
+let cachedToken: string | null = null;
+let tokenPromise: Promise<string | null> | null = null;
+
+// Async function to get token
+async function getAuthToken(): Promise<string | null> {
+  if (cachedToken) return cachedToken;
+
+  if (tokenPromise) return tokenPromise;
+
+  tokenPromise = (async () => {
+    try {
+      if (typeof window !== 'undefined') {
+        const { getSession } = await import('next-auth/react');
+        const session = await getSession();
+        cachedToken = session?.accessToken || null;
+        return cachedToken;
+      }
+    } catch (_error) {
+      // Fallback to localStorage
+      try {
+        const authStorage = localStorage.getItem('auth-storage');
+        if (authStorage) {
+          const parsed = JSON.parse(authStorage);
+          cachedToken = parsed?.state?.token || null;
+          return cachedToken;
+        }
+      } catch (__error) {
+        // All methods failed
+      }
+    }
+    return null;
+  })();
+
+  return tokenPromise;
+}
+
+// Function to clear token cache (call on logout)
+export function clearAuthTokenCache(): void {
+  cachedToken = null;
+  tokenPromise = null;
+}
+
 // สร้าง Axios Instance หลัก
 const apiClient: AxiosInstance = axios.create({
   baseURL,
@@ -28,20 +71,11 @@ apiClient.interceptors.request.use(
     }
 
     // 2. Authentication Token Injection
-    // ดึง Token จาก Zustand persist store (localStorage)
+    // ดึง Token จาก NextAuth session ผ่าน getSession()
     if (typeof window !== 'undefined') {
-      try {
-        const authStorage = localStorage.getItem('auth-storage');
-        if (authStorage) {
-          const parsed = JSON.parse(authStorage);
-          const token = parsed?.state?.token;
-
-          if (token) {
-            config.headers['Authorization'] = `Bearer ${token}`;
-          }
-        }
-      } catch (_error) {
-        // Auth token retrieval failed - request will proceed without token
+      const token = await getAuthToken();
+      if (token) {
+        config.headers['Authorization'] = `Bearer ${token}`;
       }
     }
 
@@ -66,8 +100,11 @@ apiClient.interceptors.response.use(
 
       // กรณี Token หมดอายุ หรือ ไม่มีสิทธิ์
       if (status === 401) {
-        // Unauthorized: redirect handled by auth interceptor
-        // สามารถเพิ่ม Logic Redirect ไปหน้า Login ได้ถ้าต้องการ
+        // Clear cached token and redirect to login
+        clearAuthTokenCache();
+        if (typeof window !== 'undefined') {
+          window.location.href = '/login';
+        }
       }
     }
     return Promise.reject(error);
diff --git a/frontend/proxy.ts b/frontend/proxy.ts
index 45143a3..96ca4aa 100644
--- a/frontend/proxy.ts
+++ b/frontend/proxy.ts
@@ -55,8 +55,9 @@ export const config = {
      * - _next/static (static files)
      * - _next/image (image optimization files)
      * - favicon.ico (favicon file)
+     * - robots.txt (robots file)
      * - images (public images)
      */
-    '/((?!api|_next/static|_next/image|favicon.ico|images).*)',
+    '/((?!api|_next/static|_next/image|favicon.ico|robots.txt|images).*)',
   ],
 };