diff --git a/api/get_user_messages.php b/api/get_user_messages.php
index 1297279..69e9d36 100644
--- a/api/get_user_messages.php
+++ b/api/get_user_messages.php
@@ -63,11 +63,11 @@ try {
 
     $params = ['user_id' => $userId];
     if ($before) {
-        $sql .= " AND created_at < :before";
+        $sql .= " AND c.created_at < :before";
         $params['before'] = $before;
     }
 
-    $sql .= " ORDER BY created_at DESC LIMIT " . $limit;
+    $sql .= " ORDER BY c.created_at DESC LIMIT " . $limit;
 
     // Log params/consulta para diagnóstico si algo falla (no sensible)
     error_log('get_user_messages.php - params: ' . json_encode(['user_id' => $userId, 'limit' => $limit, 'before' => $before]));