diff -u b/core/modules/aggregator/src/Plugin/views/row/Rss.php b/core/modules/aggregator/src/Plugin/views/row/Rss.php
--- b/core/modules/aggregator/src/Plugin/views/row/Rss.php
+++ b/core/modules/aggregator/src/Plugin/views/row/Rss.php
@@ -79,7 +79,7 @@
       '#options' => $this->options,
       '#row' => $item,
     );
-    return $this->renderer->renderRoot($build);
+    return  \Drupal::service('renderer')->renderRoot($build);
   }
 
 }