问暂存服务器中的GoogleWebAuthorizationBroker.AuthorizeAsync失败

EN

String gpath = Server.MapPath("credentials/siteAPI.json");
UserCredential credential;

string credPath = Server.MapPath("credentials");

using (var stream = new FileStream(gpath, FileMode.Open, FileAccess.Read))
{
      credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                    GoogleClientSecrets.Load(stream).Secrets,
                    new[] { CalendarService.Scope.Calendar },//
                    "xx@ccc.com",
                    CancellationToken.None,
                     new AppDataFileStore(credPath)
                    ).Result;
}

System.AggregateException: One or more errors occurred.
---> System.ComponentModel.Win32Exception: Access is denied
    at Microsoft.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
    at Microsoft.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccess(Task task)
    at Google.Apis.Auth.OAuth2.GoogleWebAuthorizationBroker.d__1.MoveNext() in C:\Users\mdril\Documents\GitHub\google-api-dotnet-client\Src\GoogleApis.Auth.DotNet4\OAuth2\GoogleWebAuthorizationBroker.cs:line 59
--- End of inner exception stack trace ---
    at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
    at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
    at System.Threading.Tasks.Task`1.get_Result()
    at z2.Page_Load(Object sender, EventArgs e) in e:\hostingspaces\cal1234\mysitecalendar.com\wwwroot\z2.aspx.cs:line 169
---> (Inner Exception #0) System.ComponentModel.Win32Exception (0x80004005): Access is denied
    at Microsoft.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
    at Microsoft.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccess(Task task)
    at Google.Apis.Auth.OAuth2.GoogleWebAuthorizationBroker.d__1.MoveNext() in C:\Users\mdril\Documents\GitHub\google-api-dotnet-client\Src\GoogleApis.Auth.DotNet4\OAuth2\GoogleWebAuthorizationBroker.cs:line 59<---