diff --git a/lib/Alchemy/Phrasea/Model/Entities/ApiOauthToken.php b/lib/Alchemy/Phrasea/Model/Entities/ApiOauthToken.php
index c9fa54f42b..48f73a8f19 100644
--- a/lib/Alchemy/Phrasea/Model/Entities/ApiOauthToken.php
+++ b/lib/Alchemy/Phrasea/Model/Entities/ApiOauthToken.php
@@ -105,7 +105,7 @@ class ApiOauthToken
      *
      * @return ApiOauthTokens
      */
-    public function setExpires(\DateTime $expires)
+    public function setExpires(\DateTime $expires = null)
     {
         $this->expires = $expires;