diff --git a/src/Events/AccessTokenCreated.php b/src/Events/AccessTokenCreated.php
index 6922c76ef..bcaf0d650 100644
--- a/src/Events/AccessTokenCreated.php
+++ b/src/Events/AccessTokenCreated.php
@@ -29,7 +29,7 @@ class AccessTokenCreated
      * Create a new event instance.
      *
      * @param  string  $tokenId
-     * @param  string  $userId
+     * @param  string|int|null  $userId
      * @param  string  $clientId
      * @return void
      */