diff --git a/src/Lib/Authenticate.php b/src/Lib/Authenticate.php
index 29f5977..e876d31 100644
--- a/src/Lib/Authenticate.php
+++ b/src/Lib/Authenticate.php
@@ -37,6 +37,8 @@ class Authenticate {
     {
         $logUser = function(int $id) use ($repository) {
             if ( null === ( $user = $repository->loadFromPk($id) ) ) {
+                $this->logout();
+
                 throw new \Exception("User not found.");
             }
 
@@ -61,7 +63,7 @@ class Authenticate {
         $this->session->destroy();
     }
 
-    public function authenticate(\Ulmus\Repository $repository, array $userLogin, string $password) : User
+    public function authenticate(\Ulmus\Repository $repository, array $userLogin, ? string $password) : User
     {
         foreach($userLogin as $field => $value) {
             $repository->or($field, $value);
@@ -111,7 +113,7 @@ class Authenticate {
             $this->cookie->delete('user.id');
         }
 
-        $this->user->logged = false;
+        $this->user && $this->user->logged = false;
 
         return $this;
     }