用于报告API的MWS GetReport函数返回null

我正在尝试拉FBA出货数据报告。我有一个运行的应用程序，成功地从亚马逊拉未发货的订单。所以基本上我把代码修改成我需要它做的FBA发货订单。我几乎没有改变工作代码来获得报告，现在GetReport函数返回null，我不知道为什么。我传入一个来自Amazon系统的reporttid。

如果有人能仔细检查一下代码，看看我是否传递了一个空对象或其他东西。

RequestReportRequest reportRequestRequest = new RequestReportRequest();
reportRequestRequest.Merchant = merchantId;
reportRequestRequest.Marketplace = marketplaceId;
reportRequestRequest.ReportType = "_GET_AMAZON_FULFILLED_SHIPMENTS_DATA_";
reportRequestRequest.StartDate = DateTime.Now.AddDays(-2);
reportRequestRequest.EndDate = DateTime.Now;
RequestReportResponse requestResponse = service.RequestReport(reportRequestRequest);
Thread.Sleep(15000);
Console.WriteLine(requestResponse.RequestReportResult.ReportRequestInfo.ReportProcessingStatus);
GetReportRequestListRequest reportRequestListRequest = new GetReportRequestListRequest();
reportRequestListRequest.Marketplace = marketplaceId;
reportRequestListRequest.Merchant = merchantId;
List<ReportRequestInfo> myListzz = new List<ReportRequestInfo>();
GetReportRequestListResponse reportRequestListResponse = new GetReportRequestListResponse();
reportRequestListResponse = service.GetReportRequestList(reportRequestListRequest);
GetReportRequestListResult reportRequestListResult = new GetReportRequestListResult();
reportRequestListResult = reportRequestListResponse.GetReportRequestListResult;
myListzz = reportRequestListResult.ReportRequestInfo;
while (myListzz[0].ReportProcessingStatus.ToString() != "_DONE_")
{
    Thread.Sleep(20000);
    reportRequestListResponse = service.GetReportRequestList(reportRequestListRequest);
    reportRequestListResult = reportRequestListResponse.GetReportRequestListResult;
    myListzz = reportRequestListResult.ReportRequestInfo;
}
GetReportListRequest listRequest = new GetReportListRequest();
listRequest.Merchant = merchantId;
listRequest.Marketplace = marketplaceId;
listRequest.ReportRequestIdList = new IdList();
listRequest.ReportRequestIdList.Id.Add(requestResponse.RequestReportResult.ReportRequestInfo.ReportRequestId);
GetReportListResponse listResponse = service.GetReportList(listRequest);

//MessageBox.Show(listResponse.GetReportListResult.ReportInfo.ToString());
GetReportListResult getReportListResult = listResponse.GetReportListResult;
GetReportRequest reportRequest = new GetReportRequest();
reportRequest.Merchant = merchantId;
reportRequest.Marketplace = marketplaceId;
reportRequest.WithReportId(getReportListResult.ReportInfo[0].ReportId);

GetReportResponse reportResponse = new GetReportResponse();
{
    reportResponse = service.GetReport(reportRequest); // <=== ERROR!!!!
}
catch (MarketplaceWebServiceException e)
{
    Console.WriteLine(e);
}
StreamReader sr = new StreamReader(reportRequest.Report);
Console.WriteLine(sr.ReadToEnd());
sr.Close();

GetReportResponse reportResponse = new GetReportResponse(); 

reportRequest.Report = File.Open("C:''AmazonReport.csv", FileMode.OpenOrCreate, FileAccess.ReadWrite);