Paypal Invoice SDK服务电话+快速结账+重复付款问题

Question

您好，我已经实施了Paypal发票，快速结账＆amp;使用自适应方法（NVP）调用的定期付款服务。它在我的本地系统上使用沙箱帐户正常工作，但在开发服务器上没有，并且在我根据请求调用paypal服务的任何地方都面临问题。

代码

    InvoiceModelAlias.PaymentTermsType paymentTermsType = (InvoiceModelAlias.PaymentTermsType)Enum.Parse(typeof(InvoiceModelAlias.PaymentTermsType),invoice.PaymentTerms.ToUpper());
    InvoiceModelAlias.CreateAndSendInvoiceRequest invoiceRequest = new InvoiceModelAlias.CreateAndSendInvoiceRequest();  
    invoiceRequest.requestEnvelope = new InvoiceModelAlias.RequestEnvelope();
    invoiceRequest.requestEnvelope.errorLanguage = "en_US";
    invoiceRequest.invoice = new InvoiceModelAlias.InvoiceType();
    invoiceRequest.invoice.currencyCode = invoice.CurrencyCode;
    invoiceRequest.invoice.merchantEmail = invoice.MerchantEmail;
    invoiceRequest.invoice.payerEmail = invoice.PayerEmail;
    invoiceRequest.invoice.paymentTerms = paymentTermsType;
    invoiceRequest.invoice.itemList = new InvoiceModelAlias.InvoiceItemListType();
    invoiceRequest.invoice.itemList.item = new List<InvoiceModelAlias.InvoiceItemType>();
    invoiceRequest.invoice.itemList.item.Add(new InvoiceModelAlias.InvoiceItemType(invoice.ItemName, Convert.ToDecimal(invoice.ItemQuantity), Convert.ToDecimal(invoice.ItemAmount)));
    InvoiceAlias.InvoiceService invoiceService;
    InvoiceModelAlias.CreateAndSendInvoiceResponse invoiceResponse = null;
    invoiceService = GetService();
    invoiceResponse = invoiceService.CreateAndSendInvoice(invoiceRequest);
    string ackRsponse = invoiceResponse.responseEnvelope.ack.ToString();

invoiceService.CreateAndSendInvoice(invoiceRequest)

异常

PayPal.Exception.ConnectionException: Invalid HTTP response The underlying connection was closed: An unexpected error occurred on a receive.
   at PayPal.HttpConnection.Execute(String payLoad, HttpWebRequest httpRequest)
   at PayPal.APIService.MakeRequestUsing(IAPICallPreHandler apiCallHandler)
   at PayPal.BasePayPalService.Call(IAPICallPreHandler apiCallHandler)
   at PayPal.Invoice.InvoiceService.CreateAndSendInvoice(CreateAndSendInvoiceRequest createAndSendInvoiceRequest, String apiUserName)
   at PayPal.Invoice.InvoiceService.CreateAndSendInvoice(CreateAndSendInvoiceRequest createAndSendInvoiceRequest)
   at DoPayments.Payments.Invoices.CreateAndSendInvoice(Invoice invoice)

请问有人帮我解决这个问题或者说明这背后的原因，因为它在本地运行良好但在开发/生产服务器上没有。

我在面对快速结账和定期付款方式时遇到的同样问题如下：

com.paypal.sdk.exceptions.FatalException: The underlying connection was closed: An unexpected error occurred on a receive.
   at com.paypal.sdk.core.nvp.NVPAPICaller.Call(String NvpRequest)
   at com.paypal.sdk.services.NVPCallerServices.Call(String requestnvp)

提前致谢。