diff --git a/Store/DoctrineDbalPostgreSqlStore.php b/Store/DoctrineDbalPostgreSqlStore.php
index f52345d..bf62fb6 100644
--- a/Store/DoctrineDbalPostgreSqlStore.php
+++ b/Store/DoctrineDbalPostgreSqlStore.php
@@ -271,7 +271,7 @@ private function unlockShared(Key $key): void
     private function filterDsn(string $dsn): string
     {
         if (!str_contains($dsn, '://')) {
-            throw new InvalidArgumentException(sprintf('String "%" is not a valid DSN for Doctrine DBAL.', $dsn));
+            throw new InvalidArgumentException(sprintf('String "%s" is not a valid DSN for Doctrine DBAL.', $dsn));
         }
 
         [$scheme, $rest] = explode(':', $dsn, 2);