diff --git a/src/SubrequestsManager.php b/src/SubrequestsManager.php
index 460ee11..dc6a959 100644
--- a/src/SubrequestsManager.php
+++ b/src/SubrequestsManager.php
@@ -69,7 +69,7 @@ class SubrequestsManager {
          ['master_request' => $master_request]
        );
        $response = $this->httpKernel
-         ->handle($request, HttpKernelInterface::MASTER_REQUEST);
+         ->handle($request, HttpKernelInterface::SUB_REQUEST);
        // Set the Content-ID header in the response.
        $content_id = sprintf('<%s>', $subrequest->requestId);
        $response->headers->set('Content-ID', $content_id);