diff --git a/cronjobs/opencast_discover_videos.php b/cronjobs/opencast_discover_videos.php
index 61d4639b..3ada125a 100644
--- a/cronjobs/opencast_discover_videos.php
+++ b/cronjobs/opencast_discover_videos.php
@@ -153,7 +153,7 @@ public function execute($last_result, $parameters = array())
         }
 
         // fix any broken playlists visibility
-        DBManager::get("UPDATE oc_playlist_seminar SET visibility = 'visible'
+        DBManager::get()->exec("UPDATE oc_playlist_seminar SET visibility = 'visible'
             WHERE visibility IS NULL or visibility = ''");
 
     }