diff --git a/test/docker_mail/templates/mailu.env b/test/docker_mail/templates/mailu.env
index 6ca40d0c4bcaf799565ec27e4b02ed8fa30f1183..f5f41bbecb66a916447af91dc14b12da9a00c93e 100644
--- a/test/docker_mail/templates/mailu.env
+++ b/test/docker_mail/templates/mailu.env
@@ -31,7 +31,7 @@ SUBNET=192.168.203.0/24
 DOMAIN={{ domain }}
 
 # Hostnames for this server, separated with comas
-HOSTNAMES={{ domain }}
+HOSTNAMES={{ maildomain }}
 
 # Postmaster local part (will append the main mail domain)
 POSTMASTER=admin