diff --git a/src/Controller/Checkout/CompleteOrderAction.php b/src/Controller/Checkout/CompleteOrderAction.php
index e9fc352e1..9c8262dfa 100644
--- a/src/Controller/Checkout/CompleteOrderAction.php
+++ b/src/Controller/Checkout/CompleteOrderAction.php
@@ -13,6 +13,7 @@
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface;
+use Symfony\Component\Security\Core\Exception\TokenNotFoundException;
 
 final class CompleteOrderAction
 {
@@ -51,6 +52,13 @@ public function __invoke(Request $request): Response
                     Response::HTTP_UNAUTHORIZED
                 )
             );
+        } catch (TokenNotFoundException $notLoggedInException) {
+            return $this->viewHandler->handle(
+                View::create(
+                    'You need to be logged in with the same user that wants to complete the order',
+                    Response::HTTP_UNAUTHORIZED
+                )
+            );
         }
 
         return $this->viewHandler->handle(View::create(null, Response::HTTP_NO_CONTENT));
diff --git a/src/Handler/CompleteOrderHandler.php b/src/Handler/CompleteOrderHandler.php
index 4342c862d..d2fc76f17 100644
--- a/src/Handler/CompleteOrderHandler.php
+++ b/src/Handler/CompleteOrderHandler.php
@@ -72,6 +72,7 @@ private function getCustomer(string $emailAddress): CustomerInterface
 
         // If the customer does not exist then it's  normal checkout
         if ($customer === null) {
+            /** @var CustomerInterface $customer */
             $customer = $this->customerFactory->createNew();
             $customer->setEmail($emailAddress);
 
@@ -80,7 +81,8 @@ private function getCustomer(string $emailAddress): CustomerInterface
 
         // If the customer does exist the user has to be logged in with this customer. Otherwise the user is not authorized to complete the checkout
         $loggedInUser = $this->loggedInUserProvider->provide();
-        if ($loggedInUser === null || $loggedInUser->getCustomer() !== $customer) {
+
+        if ($loggedInUser->getCustomer() !== $customer) {
             throw new NotLoggedInException();
         }