diff --git a/auth/oidc/classes/event/action_failed.php b/auth/oidc/classes/event/action_failed.php
index ff99cb06e..ae0c8885a 100644
--- a/auth/oidc/classes/event/action_failed.php
+++ b/auth/oidc/classes/event/action_failed.php
@@ -44,7 +44,7 @@ public static function get_name() {
      * @return string
      */
     public function get_description() {
-        return $this->data['other'];
+        return json_encode($this->data['other']);
     }
 
     /**