diff --git a/attestation/index.php b/attestation/index.php
index 7ef5431b0f1e9a73531bc6c43d8d03fe5d41faa2..498d267a8ea07f291252f39e56faf367964d2cf6 100644
--- a/attestation/index.php
+++ b/attestation/index.php
@@ -6,6 +6,7 @@
   // require_once('../doc/error_for_all.php');
 define('WP_USE_THEMES', false);
 require_once("../../../../wp-load.php");
+require_once("../doc/error_for_all.php");
 
 $classcodeUrl='';
 if(empty($_SERVER["HTTPS"])){
diff --git a/oc_api/OpenClassroomsAPI.php b/oc_api/OpenClassroomsAPI.php
index 39a91b6cf56464b7dd402ed52ca483b381dd1af4..4d68e22762309cc0b59f62b9ce7d24399c40baa5 100644
--- a/oc_api/OpenClassroomsAPI.php
+++ b/oc_api/OpenClassroomsAPI.php
@@ -414,7 +414,10 @@ class OpenClassroomsAPI {
 	$this->user_data = get_user_meta($user_id, 'OpenClassroomsAPI/UserData', true);
       } else {
 	session_start();
- 	$this->user_data = $_SESSION['OpenClassroomsAPI/UserData'];
+	if (isset($_SESSION['OpenClassroomsAPI/UserData']))
+	  $this->user_data = $_SESSION['OpenClassroomsAPI/UserData'];
+	else
+	  $this->user_data = array();
       }
     }
     if ($value !== NULL) {