diff --git a/INSTALACION.md b/INSTALACION.md
index 096dd04..73042e8 100644
--- a/INSTALACION.md
+++ b/INSTALACION.md
@@ -95,7 +95,7 @@ bot/
 │   └── BotService.php       # Lógica del bot
 └── assets/
     ├── css/styles.css       # Estilos
-    └── js/app.js            # JavaScript
+    └── js/app_simple.js            # JavaScript
 ```
 
 ## 🎨 Personalización
diff --git a/assets/js/app.js b/assets/js/app.js
index ab084ac..38221cb 100644
--- a/assets/js/app.js
+++ b/assets/js/app.js
@@ -507,24 +507,41 @@ class WhatsAppBotManager {
     }
 
     async loadMessageUsers() {
+        const userSelect = document.getElementById('message-recipient');
+        const templateSelect = document.getElementById('message-template');
+
+        // Mostrar estados de carga
+        if (userSelect) userSelect.innerHTML = '<option value="">Cargando usuarios...</option>';
+        if (templateSelect) templateSelect.innerHTML = '<option value="">Cargando plantillas...</option>';
+
         try {
             const usersResponse = await this.apiCall('get_users.php');
             const templatesResponse = await this.apiCall('get_templates.php');
             
-            let users = usersResponse;
+            let users = [];
             if (usersResponse && usersResponse.success && Array.isArray(usersResponse.data)) {
                 users = usersResponse.data;
+            } else if (Array.isArray(usersResponse)) {
+                users = usersResponse;
             }
             
-            let templates = templatesResponse;
+            let templates = [];
             if (templatesResponse && templatesResponse.success && Array.isArray(templatesResponse.data)) {
                 templates = templatesResponse.data;
+            } else if (Array.isArray(templatesResponse)) {
+                templates = templatesResponse;
             }
-            
+
+            console.log('loadMessageUsers - users:', users.length, 'templates:', templates.length);
+
+            // Actualizar selects
             this.updateMessageUserSelect(users);
             this.updateTemplateSelect(templates);
         } catch (error) {
-            this.showError('Error cargando datos de mensaje: ' + error.message);
+            console.error('Error loadMessageUsers:', error);
+            if (userSelect) userSelect.innerHTML = '<option value="">Error cargando usuarios</option>';
+            if (templateSelect) templateSelect.innerHTML = '<option value="">Error cargando plantillas</option>';
+            this.showError('Error cargando usuarios o plantillas: ' + (error.message || error));
         }
     }
 
diff --git a/assets/js/app_simple.js b/assets/js/app_simple.js
index 5cfb094..019ed1a 100644
--- a/assets/js/app_simple.js
+++ b/assets/js/app_simple.js
@@ -744,23 +744,50 @@ class SimpleWhatsAppManager {
     async loadconversations() {
         this.log('Cargando interfaz de mensajes');
 
+        const userSelect = document.getElementById('message-recipient');
+        const templateSelect = document.getElementById('message-template');
+
+        if (userSelect) userSelect.innerHTML = '<option value="">Cargando usuarios...</option>';
+        if (templateSelect) templateSelect.innerHTML = '<option value="">Cargando plantillas...</option>';
+
         try {
             // Cargar usuarios para el select
             const usersResponse = await this.apiCall('get_users.php');
-
-            if (usersResponse && usersResponse.success) {
-                this.populateUsersSelect(usersResponse.data || []);
+            let users = [];
+            if (usersResponse && usersResponse.success && Array.isArray(usersResponse.data)) {
+                users = usersResponse.data;
+            } else if (Array.isArray(usersResponse)) {
+                users = usersResponse;
             }
 
             // Cargar plantillas para el select
             const templatesResponse = await this.apiCall('get_templates.php');
+            let templates = [];
+            if (templatesResponse && templatesResponse.success && Array.isArray(templatesResponse.data)) {
+                templates = templatesResponse.data;
+            } else if (Array.isArray(templatesResponse)) {
+                templates = templatesResponse;
+            }
 
-            if (templatesResponse && templatesResponse.success) {
-                this.populateTemplatesSelect(templatesResponse.data || []);
+            this.log(`Usuarios cargados: ${users.length}, Plantillas cargadas: ${templates.length}`);
+
+            if (users.length > 0) {
+                this.populateUsersSelect(users);
+            } else if (userSelect) {
+                userSelect.innerHTML = '<option value="">No hay usuarios</option>';
+            }
+
+            if (templates.length > 0) {
+                this.populateTemplatesSelect(templates);
+            } else if (templateSelect) {
+                templateSelect.innerHTML = '<option value="">No hay plantillas</option>';
             }
 
         } catch (error) {
-            this.showError('Error cargando datos para mensajes: ' + error.message);
+            console.error('Error loadconversations:', error);
+            if (userSelect) userSelect.innerHTML = '<option value="">Error cargando usuarios</option>';
+            if (templateSelect) templateSelect.innerHTML = '<option value="">Error cargando plantillas</option>';
+            this.showError('Error cargando datos para mensajes: ' + (error.message || error));
         }
     }
 
diff --git a/index.php b/index.php
index bf30d3a..a1000fd 100644
--- a/index.php
+++ b/index.php
@@ -280,8 +280,11 @@ try {
             <div class="row">
                 <div class="col-lg-6">
                     <div class="card">
-                        <div class="card-header">
+                        <div class="card-header d-flex justify-content-between align-items-center">
                             <h5><i class="fas fa-paper-plane"></i> Enviar Mensaje</h5>
+                            <div>
+                                <button class="btn btn-sm btn-secondary" onclick="whatsappManager.loadconversations()">🔄 Actualizar</button>
+                            </div>
                         </div>
                         <div class="card-body">
                             <form id="send-message-form">
@@ -642,7 +645,7 @@ try {
     <!-- Scripts -->
     <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>
     <script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
-    <script src="./assets/js/app_simple.js?v=1"></script>
+    <script src="./assets/js/app_simple.js?v=2"></script>
     <script>
         // Función de diagnóstico mejorada
         function runDiagnostic() {
diff --git a/verificar_sistema.php b/verificar_sistema.php
index 4b3ca58..010cfe6 100644
--- a/verificar_sistema.php
+++ b/verificar_sistema.php
@@ -67,7 +67,7 @@
                                 <li>index.php - Sistema de login ✓</li>
                                 <li>login.php - Autenticación ✓</li>
                                 <li>logout.php - Cerrar sesión ✓</li>
-                                <li>assets/js/app.js - Corregido SES ✓</li>
+                                <li>assets/js/app_simple.js - Corregido SES ✓</li>
                             </ul>
                         </div>
                     </div>