diff --git a/symfony/mailer/4.3/manifest.json b/symfony/mailer/4.3/manifest.json
index ef7e6d00d..778e5f68b 100644
--- a/symfony/mailer/4.3/manifest.json
+++ b/symfony/mailer/4.3/manifest.json
@@ -3,7 +3,7 @@
         "config/": "%CONFIG_DIR%/"
     },
     "env": {
-        "#1": "MAILER_DSN=smtp://localhost"
+        "#1": "MAILER_DSN=null://null"
     },
     "docker-compose": {
         "docker-compose.override.yml": {