照着视频写的单文本消息回复，为什么总是成功不了

if(strtolower($postObj->MsgType) == 'text'){

if($postObj->Content == '你好'){

$template = "<xml>

<ToUserName><![CDATA[%s]]></ToUserName>

<FromUserName><![CDATA[%s]]></FromUserName>

<CreateTime>%s</CreateTime>

<MsgType><![CDATA[%s]]></MsgType>

<Content><![CDATA[%s]]></Content>

</xml>"

$fromUser = $postObj->ToUserName;

$toUser = $postObj->FromUserName;

$time = time();

$content = "您好，感谢您的关注！";

$msgType = 'text';

$info = sprintf($template,$toUser,$fromUser,$time,$msgType,$content);

echo $info;

}

}