diff --git a/lib/src/suggestions_box_controller.dart b/lib/src/suggestions_box_controller.dart
index 127c7452..df9586e0 100644
--- a/lib/src/suggestions_box_controller.dart
+++ b/lib/src/suggestions_box_controller.dart
@@ -14,7 +14,7 @@ class SuggestionsBoxController {
   void open() {
     if (_isOpened) return;
     assert(overlayEntry != null);
-    Overlay.of(context)!.insert(overlayEntry!);
+    Overlay.of(context)?.insert(overlayEntry!);
     _isOpened = true;
   }