data:"{"page":"pages/index/index"}" fail:ƒ fail() method:"POST" success:ƒ success(res) url:"https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token" + '我的token' 这种操作为什么会失败 "errcode":40169,"errmsg":"invalid length for scene, or the data is not json string hint: [60133e622]"

post访问生成二维码接口：http://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=ACCESS_TOKEN返回{"errcode":40169,"errmsg":"invalid length for scene, or the data is not json string hint: [vN3K0a0374e626]"}异常，这是什么异常啊？