diff --git a/roles/mail_server/molecule/default/tests/test_optional.py b/roles/mail_server/molecule/default/tests/test_optional.py
index 268120e1d6a80124963eee0806b16cad3fe188ec..8e893c59feaeb88c0227723ab3c31582ebf06ecd 100644
--- a/roles/mail_server/molecule/default/tests/test_optional.py
+++ b/roles/mail_server/molecule/default/tests/test_optional.py
@@ -54,7 +54,7 @@ def test_local_aliases(host):
     Tests if local aliases are configured correctly.
     """
 
-    message_id = str(uuid.uuid4())
+    message_id = "%s@localhost" % str(uuid.uuid4())
 
     send = host.run('swaks --header %s --suppress-data --to root@localhost', "Message-Id: <%s>" % message_id)
     time.sleep(1)