FedEx跟踪-无法省略ParentCredentials-错误消息：“身份验证失败”，错误代码1000

Question

我正在尝试通过使用开发者帐户凭据（UserCredentials）来获取FedEx Tracking API的响应，并且由于我不是兼容用户，所以我不拥有ParentCredentials。

代码如下：

            TrackRequest request = new TrackRequest();

            request.WebAuthenticationDetail = new WebAuthenticationDetail();
            request.WebAuthenticationDetail.UserCredential = new WebAuthenticationCredential();
            request.WebAuthenticationDetail.UserCredential.Key = "XXX"; // Replace "XXX" with the Key
            request.WebAuthenticationDetail.UserCredential.Password = "XXX"; // Replace "XXX" with the Password
            request.WebAuthenticationDetail.ParentCredential = null;

            request.ClientDetail = new ClientDetail();
            request.ClientDetail.AccountNumber = "XXX"; // Replace "XXX" with the client's account number
            request.ClientDetail.MeterNumber = "XXX"; // Replace "XXX" with the client's meter number

            request.TransactionDetail = new TransactionDetail();
            request.TransactionDetail.CustomerTransactionId = "***Track Request using VC#***";  //This is a reference field for the customer.  Any value can be used and will be provided in the response.

            request.Version = new VersionId();

            // Tracking information
            request.SelectionDetails = new TrackSelectionDetail[1] { new TrackSelectionDetail() };
            request.SelectionDetails[0].PackageIdentifier = new TrackPackageIdentifier();
            request.SelectionDetails[0].PackageIdentifier.Value = "123456789012"; // Replace "XXX" with tracking number or door tag
            //if (usePropertyFile()) //Set values from a file for testing purposes
            //{
            //    request.SelectionDetails[0].PackageIdentifier.Value = getProperty("trackingnumber");
            //}
            request.SelectionDetails[0].PackageIdentifier.Type = TrackIdentifierType.TRACKING_NUMBER_OR_DOORTAG;

            // Date range is optional.
            // If omitted, set to false
            //request.SelectionDetails[0].ShipDateRangeBegin = DateTime.Parse("06/18/2012"); //MM/DD/YYYY
            request.SelectionDetails[0].ShipDateRangeEnd = request.SelectionDetails[0].ShipDateRangeBegin.AddDays(0);
            request.SelectionDetails[0].ShipDateRangeBeginSpecified = false;
            request.SelectionDetails[0].ShipDateRangeEndSpecified = false;

            // Include detailed scans is optional.
            // If omitted, set to false
            request.ProcessingOptions = new TrackRequestProcessingOptionType[1];
            request.ProcessingOptions[0] = TrackRequestProcessingOptionType.INCLUDE_DETAILED_SCANS;

所以，这只是每个开发人员用户都可以访问的常规示例，主要区别在于我不使用ParentCredentials。

用于访问API的端点为：https://ws.fedex.com/web-services/track

我使用的UserCredentials有效。

我得到的响应包含错误消息和该问题标题中的错误代码。我该如何避免呢？