diff --git a/EventListener/FlashMessageListener.php b/EventListener/FlashMessageListener.php
index bf320a1..07f1366 100644
--- a/EventListener/FlashMessageListener.php
+++ b/EventListener/FlashMessageListener.php
@@ -48,6 +48,11 @@ public function onKernelResponse(FilterResponseEvent $event)
             return;
         }
 
+        // If there is no session, there can't be any flash messages in it
+        if (!$this->session->isStarted()) {
+            return;
+        }
+
         $flashBag = $this->session->getFlashBag();
         $flashes = $flashBag->all();