diff --git a/ariadne/settings.py b/ariadne/settings.py
index a603813..0349825 100644
--- a/ariadne/settings.py
+++ b/ariadne/settings.py
@@ -126,6 +126,7 @@ class Settings:
         default_groups = [g for g in (_env("DEFAULT_USER_GROUPS", "dev")).split(",") if g.strip()]
 
         mailu_db_port = _env_int("MAILU_DB_PORT", 5432)
+        mailu_domain = _env("MAILU_DOMAIN", "bstein.dev")
         smtp_port = _env_int("SMTP_PORT", 25)
 
         return cls(
@@ -148,7 +149,7 @@ class Settings:
             account_allowed_groups=allowed_groups,
             allowed_flag_groups=flag_groups,
             default_user_groups=default_groups,
-            mailu_domain=_env("MAILU_DOMAIN", "bstein.dev"),
+            mailu_domain=mailu_domain,
             mailu_sync_url=_env(
                 "MAILU_SYNC_URL",
                 "http://mailu-sync-listener.mailu-mailserver.svc.cluster.local:8080/events",