无法在指定时间内验证复制源

我创建了简单的.net核心web api应用程序,在其中添加了一个新的api空控制器,并添加了用于从azure文件共享获取图像/文件并上载到azure blob存储的代码。

这是我在控制器中编写的代码:

 // GET: api/UploadFiletoBlob
    [HttpGet]
    public async Task<string> UploadFiletoBlob()
    {
        // Retrieve the connection string for use with the application. The storage connection string is stored
        // in an environment variable on the machine running the application called storageconnectionstring.
        // If the environment variable is created after the application is launched in a console or with Visual
        // Studio, the shell needs to be closed and reloaded to take the environment variable into account.
        //string storageConnectionString = Environment.GetEnvironmentVariable("Storageconnectionstring");

        // Check whether the connection string can be parsed.
        if (CloudStorageAccount.TryParse(storageConnectionString, out storageAccount))
        {
            try
            {
                // Create a CloudFileClient object for credentialed access to Azure Files.
                CloudFileClient fileClient = storageAccount.CreateCloudFileClient();

                // Get a reference to the file share we created previously.
                CloudFileShare share = fileClient.GetShareReference(fileshareName);

                // Ensure that the share exists.
                if (await share.ExistsAsync())
                {
                    // Get a reference to the root directory for the share.
                    CloudFileDirectory rootDir = share.GetRootDirectoryReference();

                    // Get a reference to the directory we created previously.
                    CloudFileDirectory sampleDir = rootDir.GetDirectoryReference(directoryName);

                    // Ensure that the directory exists.
                    if (await sampleDir.ExistsAsync())
                    {
                        // Get a reference to the file we created previously.
                        sourceFile = sampleDir.GetFileReference(sourceFileName);

                        // Ensure that the file exists.
                        if (await sourceFile.ExistsAsync())
                        {
                            // Get a reference to the blob to which the file will be uploaded.
                            CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
                            CloudBlobContainer container = blobClient.GetContainerReference(containerName);
                            // Ensure that the container exists.
                            if (await container.ExistsAsync())
                            {
                                CloudBlockBlob destBlob = container.GetBlockBlobReference(sourceFile.Name);
                                // Create a SAS for the file that's valid for 24 hours.
                                // Note that when you are copying a file to a blob, or a blob to a file, you must use a SAS
                                // to authorize access to the source object, even if you are copying within the same
                                // storage account.
                                string fileSas = sourceFile.GetSharedAccessSignature(new SharedAccessFilePolicy()
                                {
                                    // Only read permissions are required for the source file.
                                    Permissions = SharedAccessFilePermissions.Read,
                                    SharedAccessExpiryTime = DateTime.UtcNow.AddHours(24)
                                });
                                // Construct the URI to the source file, including the SAS token.
                                Uri fileSasUri = new Uri(sourceFile.StorageUri.PrimaryUri.ToString() + fileSas);
                                // Upload the file to the blob.
                                await destBlob.StartCopyAsync(fileSasUri);
                                // Write the contents of the file to the output window.
                                Debug.WriteLine("Successfully uploaded the file into blob: {0}", sourceFile.Name);                                 
                            }
                        }
                    }
                }
            }
            catch (StorageException ex)
            {
                Console.WriteLine("Error returned from the service: {0}", ex.Message);
                return "Failed to upload the file into storage blob";
            }
            return $"Successfully uploaded the file into storage blob: {sourceFile.Name}";
        }
        else
        {
            Debug.WriteLine(
                "A connection string has not been defined in the system environment variables. " +
                "Add a environment variable named 'storageconnectionstring' with your storage " +
                "connection string as a value.");
            return "A connection string has not been defined in the system environment variables. " +
                "Add a environment variable named 'storageconnectionstring' with your storage " +
                "connection string as a value.";
        }
    }

但是当运行我的应用程序时,我在这行代码中随机得到了下面的异常 await destBlob.StartCopyAsync(fileSasUri); .

无法在指定的时间内验证复制源

完成 堆栈跟踪 以上例外情况:

在Microsoft.WindowsAzure.Storage.Core.Executor.Executor.dúu 4 1.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter 1.获取结果() 在Microsoft.WindowsAzure.Storage.Blob.CloudBlob上。<>c}u DisplayClass111Өu 0。<bӨu 0>d.MoveNext() ---从引发异常的上一个位置的堆栈结束跟踪--- 在System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() 在System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(任务任务) 在System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() 下载文件webapi.Controllers.DownloadFilesController.d\uuu 9.MoveNext(),地址:E:\XXX\XXX\DownloadFilesWebAPI\Controllers\DownloadFilesController.cs:line 98

如何解决这个问题?