发送客服消息，errorcode:40101,?

请求接口：https://api.weixin.qq.com/cgi-bin/message/custom/business/send?access_token=xxx
请求方法： post application/json; encoding=utf-8
请求参数：
{"touser":"xxx","msgtype":"text","link":{"title":"500","description":"dsfdsf","url":"https://skill2-mini.yxgames.com:8443/","thumb_url":"https://skill2-mini.yxgames.com:8443/static/h-ui.admin/images/admin-login-bg.jpg"}}
  返回：{
    "errcode": 40101,
    "errmsg": "missing parameter rid: 63005e03-42fcaaae-68a7403c"
}