Azure Blob存储下载:服务器无法进行身份验证，但重试时可以

我在本地电脑上使用客户端azure SDK时遇到了一个真正的ODD问题。

使用CloudBlobClient上传和删除文件的工作方式很有魅力，但当尝试下载文件时，我会遇到身份验证异常（基本上是403 Forbidden）。但是，如果我重试相同的代码，它在下次时工作正常
有人知道为什么吗？？？

以下是一些显示问题的简化代码：

    string blobEndpoint = "http://???.blob.core.windows.net";
    string accountName = "???";
    string accountKey = "???";
        while(retry)
        {
            FileStream stream = new FileStream("C:''temp''mydownload.jpg", FileMode.Append);
            try
            {
                CloudBlobClient blobClient =
                new CloudBlobClient(new Uri(blobEndpoint), new StorageCredentialsAccountAndKey(accountName, accountKey));
                CloudBlob blob = blobClient.GetBlobReference("documents/drive.png");
                blob.DownloadToStream(stream);
                retry = false;
            }
            catch (Exception ee)
            {
                if (MessageBox.Show(ee.Message.ToString(), "ARGH!", MessageBoxButtons.RetryCancel) != System.Windows.Forms.DialogResult.Retry)
                    retry = false;
            }
            finally
            {
                stream.Flush();
                stream.Close();
            }
        }

正在生成的异常为：

    Microsoft.WindowsAzure.StorageClient.StorageClientException was unhandled
  Message=Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
  Source=Microsoft.WindowsAzure.StorageClient
  StackTrace:
       at Microsoft.WindowsAzure.StorageClient.Tasks.Task`1.get_Result()
       at Microsoft.WindowsAzure.StorageClient.Tasks.Task`1.Execute()
       at Microsoft.WindowsAzure.StorageClient.RequestWithRetry.RequestWithRetrySyncImpl[TResult](ShouldRetry retryOracle, SynchronousTask`1 syncTask)
       at Microsoft.WindowsAzure.StorageClient.TaskImplHelper.ExecuteSyncTaskWithRetry[TResult](SynchronousTask`1 syncTask, RetryPolicy policy)
       at Microsoft.WindowsAzure.StorageClient.CloudBlob.DownloadToStream(Stream target, BlobRequestOptions options)
       at Microsoft.WindowsAzure.StorageClient.CloudBlob.DownloadToStream(Stream target)
       at TestAzure.Form1.button1_Click(Object sender, EventArgs e) in c:'users'richard.donaldson'documents'visual studio 2010'Projects'TestAzure'TestAzure'Form1.cs:line 41
       at System.Windows.Forms.Control.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
       at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ButtonBase.WndProc(Message& m)
       at System.Windows.Forms.Button.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(Form mainForm)
       at TestAzure.Program.Main() in c:'users'richard.donaldson'documents'visual studio 2010'Projects'TestAzure'TestAzure'Program.cs:line 18
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.Net.WebException
       Message=The remote server returned an error: (403) Forbidden.
       Source=System
       StackTrace:
            at System.Net.HttpWebRequest.GetResponse()
            at Microsoft.WindowsAzure.StorageClient.EventHelper.ProcessWebResponseSync(WebRequest req, EventHandler`1 handler, Object sender)
       InnerException: {"The remote server returned an error: (403) Forbidden."}