Yii2.0 发布在 Nginx 上访问报错 [ 求助交流 ]

部署网站到Nginx服务器上面，却报这个错误,不知如何解决，求大神指点，在线等~，谢谢
PHP Warning – yii\base\ErrorException
register_shutdown_function(): Invalid shutdown callback '' passed

 public function init()
    {
        parent::init();
        register_shutdown_function(function () {
            // make regular flush before other shutdown functions, which allows session data collection and so on
            $this->flush();
            // make sure log entries written by shutdown functions are also flushed
            // ensure "flush()" is called last when there are multiple shutdown functions
            register_shutdown_function([$this, 'flush'], true);
        });
    }