wx.openOfflinePayView 接口权限已向服务商申请开通，之前是提示 fail no permission的，权限开通后调起微信付款码时，出现 openOfflinePayView:fail，

签名结果与支付接口调试工具签名结果一致，目前还尚未找到具体原因

wx.request({
  url: 'sign-url',
  success: function(response) {
    if(response.data.errcode==0) {

      wx.openOfflinePayView({
        appId: response.data.appId,
        timeStamp: response.data.timeStamp,
        nonceStr: response.data.nonceStr,
        package: response.data.package, // package格式为：mch_id=商户号
        signType: "MD5",
        paySign: response.data.paySign,

        success: function (a) {
          console.log(a);
        },
        fail: function (a) {
          console.log(a);
        },
        complete: function (a) {
          console.log(a);
        }
      });
    }
  }
})