diff --git a/app/assets/javascripts/pretty-text/oneboxer.js.es6 b/app/assets/javascripts/pretty-text/oneboxer.js.es6
index cb7d94b641f..034120502cf 100644
--- a/app/assets/javascripts/pretty-text/oneboxer.js.es6
+++ b/app/assets/javascripts/pretty-text/oneboxer.js.es6
@@ -86,7 +86,7 @@ function loadNext(ajax) {
           removeLoading = false;
           loadingQueue.unshift({ url, refresh, $elem, categoryId, topicId });
         } else {
-          setFailedCache[normalize(url)] = true;
+          setFailedCache(normalize(url), true);
         }
       }
     )