diff --git a/app/Http/Controllers/BranchControlController.php b/app/Http/Controllers/BranchControlController.php
index 0755297..84eda71 100644
--- a/app/Http/Controllers/BranchControlController.php
+++ b/app/Http/Controllers/BranchControlController.php
@@ -80,8 +80,8 @@ class BranchControlController extends Controller
                         $roomName => [
                             'is_online' => $room->is_online,
                             'status' => $room->status?->value ?? null,
-                            'started_at' => optional($room->started_at)->timezone('Asia/Taipei')->format('Y-m-d H:i:s'),
-                            'ended_at'   => optional($room->ended_at)->timezone('Asia/Taipei')->format('Y-m-d H:i:s'),
+                            'started_at' => $room->started_at ? $room->started_at->timezone('Asia/Taipei')->format('Y-m-d H:i:s') : null,
+                            'ended_at'   => $room->ended_at ? $room->ended_at->timezone('Asia/Taipei')->format('Y-m-d H:i:s') : null
                         ]
                     ];
                 }),