diff --git a/AIDevGallery/Samples/WCRAPIs/KnowledgeRetrieval.xaml.cs b/AIDevGallery/Samples/WCRAPIs/KnowledgeRetrieval.xaml.cs
index 5d9bf3f3..79928dbb 100644
--- a/AIDevGallery/Samples/WCRAPIs/KnowledgeRetrieval.xaml.cs
+++ b/AIDevGallery/Samples/WCRAPIs/KnowledgeRetrieval.xaml.cs
@@ -152,6 +152,8 @@ private void CleanUp()
         _indexer?.RemoveAll();
         _indexer?.Dispose();
         _indexer = null;
+        cts?.Dispose();
+        cts = null;
     }
 
     public void Dispose()