diff --git a/src/Symfony/Component/Notifier/Exception/IncompleteDsnException.php b/src/Symfony/Component/Notifier/Exception/IncompleteDsnException.php
index 34d4e3f116748..3ebcc58d6cd2f 100644
--- a/src/Symfony/Component/Notifier/Exception/IncompleteDsnException.php
+++ b/src/Symfony/Component/Notifier/Exception/IncompleteDsnException.php
@@ -24,7 +24,7 @@ public function __construct(string $message, string $dsn = null, ?\Throwable $pr
     {
         $this->dsn = $dsn;
         if ($dsn) {
-            $message = sprintf('Invalid "%s" notifier DSN: ', $dsn).$message;
+            $message = sprintf('Invalid "%s" notifier DSN: %s', $dsn, $message);
         }
 
         parent::__construct($message, 0, $previous);