试图获取非对象的属性在计划中

Question

我正在使用laravel 5.5，我想安排一项任务，我尝试使用以下代码

protected function schedule(Schedule $schedule)
{
    $user_id = Auth::user()->id;
    $data = MenterRequest::where('menter_subscriber_id','=',$user_id)->first();
    $sentTime  =  $data->created_at;
    $currentTime = Carbon::now();
    $diff_in_hours = $sentTime->diffInHours($currentTime);
    if($diff_in_hours >=75)
    {
        $schedule->call(function () {
        DB::table('menter_requests')->where('menter_subscriber_id','=',$user_id)->delete();
        })->everyMinute();
    }

} 

如果尝试获取身份验证用户ID 尝试获取非对象属性错误，则用户已经过身份验证或已登录。