diff --git a/docker-compose.yml b/docker-compose.yml
index fe197e5b15d..4115b339157 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -172,6 +172,7 @@ services:
       CAPYBARA_SERVER_PORT: 3000
       CAPYBARA_DYNAMIC_BIND_IP: 1
       CAPYBARA_APP_HOSTNAME: backend-test
+      OPENPROJECT_EMAIL__DELIVERY__METHOD: test
       OPENPROJECT_CLI_PROXY: http://frontend-test:4200
       OPENPROJECT_TESTING_NO_HEADLESS: "true"
       OPENPROJECT_TESTING_AUTO_DEVTOOLS: "true"