Ensure DOM is loaded before binding the global AJAX error handler.

assets/js/general_functions.js

@@ -25,9 +25,11 @@ window.GeneralFunctions = window.GeneralFunctions || {};
     /**
      * Register global error handler.
      */
+    document.addEventListener('DOMContentLoaded', function() {
         $(document).ajaxError(function (event, jqxhr, settings, thrownError) {
             GeneralFunctions.ajaxFailureHandler(jqxhr, settings, thrownError);
         });
+    });
 
     /**
      * This functions displays a message box in the admin array. It is useful when user