diff --git a/compose/seatable-server.yml b/compose/seatable-server.yml
index 4153782..453b523 100644
--- a/compose/seatable-server.yml
+++ b/compose/seatable-server.yml
@@ -40,7 +40,7 @@ services:
       - SEATABLE_EMAIL_HOST=${SEATABLE_EMAIL_HOST:-}
       - SEATABLE_EMAIL_HOST_USER=${SEATABLE_EMAIL_HOST_USER:-}
       - SEATABLE_EMAIL_HOST_PASSWORD=${SEATABLE_EMAIL_HOST_PASSWORD:-}
-      - SEATABLE_EMAIL_PORT=${SEATABLE_EMAIL_PORT:-}
+      - SEATABLE_EMAIL_PORT=${SEATABLE_EMAIL_PORT:-25}
       - SEATABLE_DEFAULT_FROM_EMAIL=${SEATABLE_DEFAULT_FROM_EMAIL:-}
       - SEATABLE_SERVER_EMAIL=${SEATABLE_SERVER_EMAIL:-}
       - SEATABLE_SHOW_TEMPLATES_LINK=${SEATABLE_SHOW_TEMPLATES_LINK:-}