Deleted the additional line based on the first feedback

packages/app/src/server/views/layout-growi/not_found.html

@@ -15,7 +15,6 @@
   </div>
   <div class="grw-container-convertible">
     {% include '../widget/page_alerts.html' %}
-    <div id="not-found-alert"></div>
   </div>
 {% endblock %}