求助：服务端push返回400，error为：cid is invalid，哪里的问题？

服务端php代码如下：

    function push_article_to_single_ios($pushid, $cid, $title, $content, $tid, $args) {
        $client = new Client($this->app_key, $this->master_secret);
        $payload = parent::get_payload($pushid, $title, $content, $tid, $args);

        $push = $client->push()->setPlatform(array('ios'))->setCid($cid)->iosNotification(
            $title, array(
                'title' => $title,
                'extras' => $payload
            )
        )->options(array(
            "sendno"=>time(),
            "time_to_live"  => OFFLINE_EXPIRE_TIME,
            'apns_production' => false
        ))->message($content, array(
            'title' => $title,
            'extras' => $payload
        ))->addAllAudience();
        $result = $push->send();
    }

返回的respon : httpcode = 400; msg : cid is invalid ;

同一个的cid，我在后台推送，是可以成功的（客户端可以收到消息）；