diff --git a/packages/frontend/src/pages/admin/relays.vue b/packages/frontend/src/pages/admin/relays.vue
index fca9776c0a..9eba68022a 100644
--- a/packages/frontend/src/pages/admin/relays.vue
+++ b/packages/frontend/src/pages/admin/relays.vue
@@ -41,7 +41,7 @@ async function addRelay() {
 		type: 'url',
 		placeholder: i18n.ts.inboxUrl,
 	});
-	if (canceled) return;
+	if (canceled || inbox == null) return;
 	misskeyApi('admin/relays/add', {
 		inbox,
 	}).then((relay: any) => {