yii2接入微信公众号，报错该公众号暂时无法提供服务 [ 2.0 版本 ]

直接贴代码

namespace frontend\controllers;

use Yii;
use core\Tkx;
use yii\web\BadRequestHttpException;
use \core\frontend\FrontendController;
use yii\filters\VerbFilter;
use yii\filters\AccessControl;
use \frontend\models\DcAccountCar;
use \frontend\models\DcCouponRec;
use \frontend\models\DcCouponKind;
use \frontend\models\DcPark;
use yii\web\ForbiddenHttpException;

class ValidationController extends \core\frontend\FrontendController
{

    public  $postObj;

    public  $fromUsername;

    public  $toUsername;

    public  $keyword;

    public  $time;

    public  $token;


    public function actions()
    {
        $weixin = $this->getWeixin();
        $this->token = $weixin['token'];
    }

    public function actionIndex()
    {
        $echoStr = Yii::$app->request->get('echostr');
        if($this->checkSignature() && Yii::$app->request->get('echostr')  ){
            echo $echoStr;
            exit;
        }else{
            $this->responseMsg();
        }
    }

    public function responseMsg()
    {
        $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
        libxml_disable_entity_loader(true);
        $this->postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
        $this->fromUsername = $this->postObj->FromUserName;
        $this->toUsername = $this->postObj->ToUserName;
        $this->keyword = trim($this->postObj->Content);
        $this->time = time();
        if( strtolower($this->postObj->MsgType)=='event'){
            if( strtolower($this->postObj->Event)=='subscribe'){
                //关注事件处理
                $this->msg_text('您已经关注了哦');
            }elseif(strtolower($this->postObj->Event)=='unsubscribe'){
                //取消关注事件处理
            }
        }else{
            if (!empty($postStr)){
                if(!empty( $this->keyword ))
                {
                    switch ($this->keyword) {
                        case '文字':
                            $this->msg_text('文字回复成功');
                            break;
                        case '图文':
                            $this->msg_picture('单图文回复成功','http://img2.md.veimg.cn/info/luojing/201105/20110518004.jpg','停开心图文回复测试成功','http://www.baidu.com');
                            break;
                        default:
                            $this->msg_text('默认回复成功');
                            break;
                    }
                }else{
                    echo "";
                }

            }else {
                echo "";
                exit;
            }

        }
    }

    private function checkSignature()
    {
        $signature = Yii::$app->request->get('signature');
        $timestamp = Yii::$app->request->get('timestamp');
        $nonce = Yii::$app->request->get('nonce');

        $token = $this->token;
        $tmpArr = array($token, $timestamp, $nonce);

        sort($tmpArr, SORT_STRING);
        $tmpStr = implode( $tmpArr );
        $tmpStr = sha1( $tmpStr );

        if( $tmpStr == $signature ){
            return true;
        }else{
            return false;
        }
    }

    //文本回复
    public function  msg_text($text){
        $textTpl = "<xml>
					<ToUserName><![CDATA[%s]]></ToUserName>
					<FromUserName><![CDATA[%s]]></FromUserName>
					<CreateTime>%s</CreateTime>
					<MsgType><![CDATA[%s]]></MsgType>
					<Content><![CDATA[%s]]></Content>
					<FuncFlag>0</FuncFlag>
					</xml>";
        $msgType = "text";
        $contentStr = $text;
        $resultStr = sprintf($textTpl, $this->fromUsername, $this->toUsername, $this->time, $msgType, $contentStr);
        echo $resultStr;
    }

    //单图文回复
    public function msg_picture($title,$pic,$desc,$url){
        $pictureTpl = "<xml>
						<ToUserName><![CDATA[%s]]></ToUserName>
						<FromUserName><![CDATA[%s]]></FromUserName>
						<CreateTime>%s</CreateTime>
						<MsgType><![CDATA[%s]]></MsgType>
						<ArticleCount>1</ArticleCount>
						<Articles>
								<item>
								<Title><![CDATA[%s]]></Title>
								<Description><![CDATA[%s]]></Description>
								<PicUrl><![CDATA[%s]]></PicUrl>
								<Url><![CDATA[%s]]></Url>
								</item>
						</Articles>
						</xml> ";
        $msgType = 'news';
        $resultStr = sprintf($pictureTpl, $this->fromUsername, $this->toUsername, $this->time, $msgType , $title, $desc, $pic, $url);
        echo $resultStr;
    }








}

token验证已经通过，但就是报错，求找错误！
注：之前写过纯PHP下的，这是yii2移植版本