Call to a member function toNotGiven() on null

[hisyamali]

    //OrderObserver

    if ($order->status === Order::STATUS_PAYMENT_VERIFY ||
        $order->status === Order::STATUS_RECEIVED) {
        $statusVerification = $order->status === Order::STATUS_PAYMENT_VERIFY ? 'Butuh Verifikasi' : Order::STATUS_PAYMENT_VERIFY;
        $statusReceived = $order->status === Order::STATUS_RECEIVED ? 'Butuh Penerusan Dana' : Order::STATUS_RECEIVED;
        if($statusVerification) {
            $message = "Pesanan #{$order->order_number} status: {$statusVerification} di Toko #{$order->merchant->name}";
        } elseif($statusReceived) {
            $message = "Pesanan #{$order->order_number} status: {$statusReceived} di Toko #{$order->merchant->name}";
        }

        Log::info('Sending notification', ['message' => $message]);
        // Kirim notifikasi
        Notification::route('telegram', env('TELEGRAM_CHAT_ID'))
            ->notify(new TelegramNotification($message));
    }

    $merchants = Merchant::all(); // Ambil semua merchant
    // Cek status merchant
    if($merchants->contains('status', Merchant::STATUS_VERIFY)) {
        foreach ($merchants as $merchant) {
            $message = "Toko #{$merchant->name} butuh verifikasi";
            Log::info('Sending notification', ['message' => $message]);
            // Kirim notifikasi
            Notification::route('telegram', env('TELEGRAM_CHAT_ID'))
                ->notify(new TelegramNotification($message));
        }
    }

   //TelegramNotification
       public function via($notifiable)
{
    return [TelegramChannel::class];
}
public function toTelegram($notifiable)
{
           $chat_id = env('TELEGRAM_CHAT_ID'); // Chat ID dari grup atau channel

    Telegram::sendMessage([
        'chat_id' => $chat_id,
        'text' => $this->message
    ]);
 }