求助大神，asp.net开发微信自动回复图文消息显示“该公众号暂时无法提供服务，请稍后再试”

求助大神，开发微信自动回复图文消息显示“该公众号暂时无法提供服务，请稍后再试”，代码如下：
 var model = new
                    {
                        toUsername = rootElement.SelectSingleNode("ToUserName").InnerText,
                        fromUsername = rootElement.SelectSingleNode("FromUserName").InnerText,
                        msgType = rootElement.SelectSingleNode("MsgType").InnerText,
                        content = rootElement.SelectSingleNode("Content").InnerText
                       
                    };
string resxml =
                            "<xml>"
                            + "<ToUserName><![CDATA[" + model.toUsername + "]]></ToUserName>"
                            + "<FromUserName><![CDATA[" + model.fromUsername + "]]></FromUserName>"
                            + "<CreateTime>" + GetCreateTime() + "</CreateTime>"
                            + "<MsgType><![CDATA[news]]></MsgType>"
                            + "<ArticleCount>1</ArticleCount>"
                            + "<Articles>"
                            + "<item>"
                            + "<Title><![CDATA[欢迎您的光临！]]></Title>"
                            + "<Description><![CDATA[非常感谢您的关注！]]></Description>"
                            + "<PicUrl><![CDATA[http://1.star530.]]></PicUrl>"
                            + "<Url><![CDATA[http://www.baidu.com/]]></Url>"
                            + "</item>"
                            + "</Articles>"
                            + "<FuncFlag>1</FuncFlag></xml>";
                       context.Response.Write(resxml);