diff --git a/client/app.js b/client/app.js
index d197137..e745a18 100644
--- a/client/app.js
+++ b/client/app.js
@@ -400,12 +400,17 @@ async function deleteModel(modelId) {
 // Collections Functions
 async function loadCollections() {
   try {
-    const response = await fetch(`${API_BASE}/collections`);
+    const headers = {};
+    if (authToken) {
+      headers['Authorization'] = `Bearer ${authToken}`;
+    }
+    
+    const response = await fetch(`${API_BASE}/collections`, { headers });
     const data = await response.json();
-    allCollections = data.collections;
+    allCollections = data.collections || [];
 
     const collectionsList = document.getElementById('collectionsList');
-    if (data.collections.length > 0) {
+    if (data.collections && data.collections.length > 0) {
       collectionsList.innerHTML = data.collections.map(collection => `
         <li>
           <a href="#" onclick="loadAllModels('', '', ${collection.id}); return false;">
@@ -420,10 +425,14 @@ async function loadCollections() {
     // Update upload modal collection select
     const uploadCollectionSelect = document.getElementById('uploadCollection');
     uploadCollectionSelect.innerHTML = '<option value="">None</option>' +
-      data.collections.map(c => `<option value="${c.id}">${escapeHtml(c.name)}</option>`).join('');
+      (data.collections ? data.collections.map(c => `<option value="${c.id}">${escapeHtml(c.name)}</option>`).join('') : '');
 
   } catch (error) {
     console.error('Error loading collections:', error);
+    const collectionsList = document.getElementById('collectionsList');
+    if (collectionsList) {
+      collectionsList.innerHTML = '<li class="loading">Error loading collections</li>';
+    }
   }
 }
 
@@ -471,12 +480,17 @@ function showCollections() {
 // Tags Functions
 async function loadTags() {
   try {
-    const response = await fetch(`${API_BASE}/tags`);
+    const headers = {};
+    if (authToken) {
+      headers['Authorization'] = `Bearer ${authToken}`;
+    }
+    
+    const response = await fetch(`${API_BASE}/tags`, { headers });
     const data = await response.json();
-    allTags = data.tags;
+    allTags = data.tags || [];
 
     const tagsList = document.getElementById('tagsList');
-    if (data.tags.length > 0) {
+    if (data.tags && data.tags.length > 0) {
       const topTags = data.tags.sort((a, b) => b.model_count - a.model_count).slice(0, 10);
       tagsList.innerHTML = topTags.map(tag => `
         <span class="tag" style="background-color: ${tag.color}" onclick="loadAllModels('', '${escapeHtml(tag.name)}', '')">
@@ -488,6 +502,10 @@ async function loadTags() {
     }
   } catch (error) {
     console.error('Error loading tags:', error);
+    const tagsList = document.getElementById('tagsList');
+    if (tagsList) {
+      tagsList.innerHTML = '<span class="loading">Error loading tags</span>';
+    }
   }
 }