diff --git a/Mode3Test/frontend/index.html b/Mode3Test/frontend/index.html
index 4e41756..782aaff 100644
--- a/Mode3Test/frontend/index.html
+++ b/Mode3Test/frontend/index.html
@@ -276,16 +276,42 @@
     );
   };
 
+  // Queue to prevent concurrent refresh calls (PocketBase auto-cancels duplicates)
+  let refreshPromise = null;
+  let lastRefreshTime = 0;
+  const REFRESH_COOLDOWN = 2000; // 2 second cooldown between refreshes
+
   const refreshGraphToken = async () => {
     try {
-      const authData = await pb.collection('users').authRefresh();
-      const meta = authData?.meta || pb?.authStore?.model?.meta || {};
-      const token = extractGraphToken(meta);
-      if (token) localStorage.setItem(GRAPH_TOKEN_KEY, token);
-      return token || '';
+      // If already refreshing, return that promise
+      if (refreshPromise) {
+        return await refreshPromise;
+      }
+      
+      // If refreshed recently, return cached token
+      if (Date.now() - lastRefreshTime < REFRESH_COOLDOWN) {
+        return getGraphToken();
+      }
+      
+      // Start new refresh
+      refreshPromise = (async () => {
+        try {
+          const authData = await pb.collection('users').authRefresh();
+          const meta = authData?.meta || pb?.authStore?.model?.meta || {};
+          const token = extractGraphToken(meta);
+          if (token) localStorage.setItem(GRAPH_TOKEN_KEY, token);
+          lastRefreshTime = Date.now();
+          return token || '';
+        } finally {
+          refreshPromise = null;
+        }
+      })();
+      
+      return await refreshPromise;
     } catch(err){
+      refreshPromise = null;
       console.warn('Graph token refresh failed:', err?.message||err);
-      return '';
+      return getGraphToken(); // Return cached token if refresh fails
     }
   }