diff -u b/simple_oauth_extras/src/Controller/Oauth2AuthorizeController.php b/simple_oauth_extras/src/Controller/Oauth2AuthorizeController.php
--- b/simple_oauth_extras/src/Controller/Oauth2AuthorizeController.php
+++ b/simple_oauth_extras/src/Controller/Oauth2AuthorizeController.php
@@ -2,15 +2,14 @@
 
 namespace Drupal\simple_oauth_extras\Controller;
 
-use GuzzleHttp\Psr7\Response;
 use Drupal\Core\Controller\ControllerBase;
-use Drupal\simple_oauth\Entities\UserEntity;
-use Symfony\Component\HttpFoundation\Request;
 use Drupal\Core\Routing\TrustedRedirectResponse;
-use League\OAuth2\Server\Exception\OAuthServerException;
+use Drupal\simple_oauth\Entities\UserEntity;
 use Drupal\simple_oauth\Plugin\Oauth2GrantManagerInterface;
-use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Bridge\PsrHttpMessage\HttpMessageFactoryInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
 
 /**
  * Oauth2AuthorizeController.
@@ -54,7 +53,7 @@
   public function authorize(Request $request) {
     $client_uuid = $request->get('client_id');
     if (empty($client_uuid)) {
-      throw OAuthServerException::invalidClient();
+      return new Response('Client authentication failed', 401);
     }
     $client_drupal_entities = $this->entityTypeManager()
       ->getStorage('consumer')
@@ -62,12 +61,12 @@
         'uuid' => $client_uuid,
       ]);
     if (empty($client_drupal_entities)) {
-      throw OAuthServerException::invalidClient();
+      return new Response('Client authentication failed', 401);
     }
 
     $client_drupal_entity = reset($client_drupal_entities);
 
-    $accessPreviouslyConfirmed = false;
+    $accessPreviouslyConfirmed = FALSE;
 
     $previous_token_entities = $this->entityTypeManager()
       ->getStorage('oauth2_token')
@@ -75,13 +74,13 @@
         'auth_user_id' => $this->currentUser()->id(),
         'client' => $client_uuid,
       ]);
-    if(!empty($previous_token_entities)){
-      $accessPreviouslyConfirmed = true;
+    if (!empty($previous_token_entities)) {
+      $accessPreviouslyConfirmed = TRUE;
     }
 
     if ($this->currentUser()
         ->isAuthenticated() && ($client_drupal_entity->get('third_party')
-        ->getString() == 0 || $accessPreviouslyConfirmed)) {
+          ->getString() == 0 || $accessPreviouslyConfirmed)) {
       if ($request->get('response_type') == 'code') {
         $grant_type = 'code';
       }
@@ -101,12 +100,13 @@
           ->hasPermission('grant simple_oauth codes');
         $auth_request->setAuthorizationApproved($can_grant_codes);
         $response = $server->completeAuthorizationRequest($auth_request,
-          new Response());
+          new \GuzzleHttp\Psr7\Response());
         $redirect_response = TrustedRedirectResponse::create(
           $response->getHeaderLine('location'),
           $response->getStatusCode(),
           $response->getHeaders()
         );
+
         return $redirect_response;
       }
     }