webman模型插入数据失败而DB插入数据没有问题,本人很困惑, 求助作者大大和各位路人大佬~

$this->model->create($params);
//如果用save需要这样
$this->model->username = $params['username'];
$this->model->password = $params['password'];
$this->model->branch_id = 1;
$this->model->save();

     /**
     * 允许修改的字段
     * @var string[]
     */
    protected $fillable = ['title', 'deleted_at'];