RadGrid BIFF导出-远程主机强制关闭了现有连接

我运行的是刚刚从Windows 2008升级的Windows Server 2012 R2。

我有一个带有图像的Telerik网格。我最近更换了服务器，现在我无法将网格导出到带有图像的biff。错误如下：

An existing connection was forcibly closed by the remote host

堆栈跟踪：

[SocketException (0x2746): An existing connection was forcibly closed by the remote host]
   System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) +249
[IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.]
   System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) +8420333
   System.Net.FixedSizeReader.ReadPacket(Byte[] buffer, Int32 offset, Int32 count) +57
   System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest) +243
   System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest) +470
   System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest) +8552078
   System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult) +230
   System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) +645
   System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) +9
   System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) +87
   System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result) +1467
   System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size) +84
   System.Net.ConnectStream.WriteHeaders(Boolean async) +816
[WebException: The underlying connection was closed: An unexpected error occurred on a send.]
   System.Net.WebClient.DownloadDataInternal(Uri address, WebRequest& request) +3407972
   System.Net.WebClient.DownloadData(Uri address) +214
   Telerik.Web.UI.ExportInfrastructure.Image.GetImageFromUrl() +226
   Telerik.Web.UI.ExportInfrastructure.XlsBiffRenderer.CreateWorksheet(Table tbl, Workbook wb) +2238
   Telerik.Web.UI.ExportInfrastructure.XlsBiffRenderer.Render() +198
   Telerik.Web.UI.Grid.Export.TableViewExporter.ExcelExportRenderForm(HtmlTextWriter nullWriter, Control form) +1057
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +131
   System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +151
   System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +49
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +150
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +131
   System.Web.UI.Page.Render(HtmlTextWriter writer) +40
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +150
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5363

这是一个动态创建的网格，它过去在旧服务器上工作。

我已经把它缩小到下面的代码。当我包含完整的URL（这是一个生成图像的ashx）时，它会失败。当我排除"https://www.someserver.com"，它工作正常，但不导出BIFF中的图像。

GridImageColumn gci = new GridImageColumn();
    gridPreview.MasterTableView.Columns.Add(gci);
    gci.HeaderText = fieldName;
    gci.UniqueName = fieldName.Replace(" ", string.Empty);
    gci.FooterText = "image";
    gci.DataImageUrlFormatString = string.Format("https://www.someserver.com/{0}{{0}}/w100/h100", cm.SiteInfo.FriendlyName);
    gci.DataImageUrlFields = new string[] { fieldName };
    gci.ImageWidth = 100;
    gci.ItemStyle.Width = 100;
    gci.HeaderStyle.Width = 100;
    gci.AllowFiltering = false;

我花了一整天的时间在这个问题上拔头发，我需要一个快速的答案来解决这个问题。。。IIS 8中是否有服务器设置？我需要防止对映像的回调失败？当代码调用生成的图像时，它无法访问该图像（听起来很荒谬，但我现在正在抓住救命稻草），这是权限问题吗。

我试过增加超时时间（我怀疑这没有帮助，因为它很快就失败了）。我运行了一个调试会话，它在预呈现时崩溃了。使用JustDecompile深入研究Telerik，我发现它在预渲染器上发挥了作用，但我想我在寻找我缺少的东西。毕竟，如果它在一台服务器上工作，它应该在我移动到的服务器上工作吗？

它在标准Excel导出中工作得很好，但当然，图像不会被嵌入。

编辑：我使用旧数据库重新激活了旧服务器（图像仍从新服务器中提取），但同样失败。这排除了一切，除了Telerik从新服务器中提取图像的方式。我可能会回去，编辑包括图像在内的所有内容，看看错误是否发生了变化。

再次编辑：好吧，我在旧服务器上更改了所有内容，阻止错误的一件事是将图像URL更改为旧服务器上的本地URL。所以，这意味着这绝对与在新服务器上获取图像有关。苏-有什么区别？是DDOS保护吗？是权限吗？（编辑：不，不是——我用消防水管"每个人"读/写，同样的问题）这让我疯了。