I am using Fiddler 1.5.1 in Windows 10 version 1909.

The application has been launched.

But I could not save the connection port.

The save button hangs

Could you attach your application log files? You could find them using the `Help - Open Application Logs Folder` menu.

attaching logs

attaching logs

[2021-03-24 14:18:44:706] [Error] [NETCore] Unexpected backend error.

System.Threading.Tasks.TaskCanceledException: The operation was canceled.

   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)

   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)

   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)

   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)

   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)

   at System.Net.Http.AuthenticationHelper.SendWithAuthAsync(HttpRequestMessage request, Uri authUri, ICredentials credentials, Boolean preAuthenticate, Boolean isProxyAuth, Boolean doRequestAuth, HttpConnectionPool pool, CancellationToken cancellationToken)

   at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)

   at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)

   at Polly.Retry.AsyncRetryEngine.ImplementationAsync[TResult](Func`3 action, Context context, CancellationToken cancellationToken, ExceptionPredicates shouldRetryExceptionPredicates, ResultPredicates`1 shouldRetryResultPredicates, Func`5 onRetryAsync, Int32 permittedRetryCount, IEnumerable`1 sleepDurationsEnumerable, Func`4 sleepDurationProvider, Boolean continueOnCapturedContext)

   at Polly.AsyncPolicy`1.ExecuteAsync(Func`3 action, Context context, CancellationToken cancellationToken, Boolean continueOnCapturedContext)

   at Polly.Wrap.AsyncPolicyWrapEngine.<>c__DisplayClass0_0`1.<<ImplementationAsync>b__0>d.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

   at Polly.Fallback.AsyncFallbackEngine.ImplementationAsync[TResult](Func`3 action, Context context, CancellationToken cancellationToken, ExceptionPredicates shouldHandleExceptionPredicates, ResultPredicates`1 shouldHandleResultPredicates, Func`3 onFallbackAsync, Func`4 fallbackAction, Boolean continueOnCapturedContext)

   at Polly.AsyncPolicy`1.ExecuteAsync(Func`3 action, Context context, CancellationToken cancellationToken, Boolean continueOnCapturedContext)

   at Polly.Wrap.AsyncPolicyWrapEngine.ImplementationAsync[TResult](Func`3 func, Context context, CancellationToken cancellationToken, Boolean continueOnCapturedContext, IAsyncPolicy`1 outerPolicy, IAsyncPolicy`1 innerPolicy)

   at Polly.AsyncPolicy`1.ExecuteAsync(Func`3 action, Context context, CancellationToken cancellationToken, Boolean continueOnCapturedContext)

   at Microsoft.Extensions.Http.PolicyHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)

   at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)

   at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)

   at FiddlerBackendSDK.Core.Http.Client.AuthenticatedHttpClient.<>c__DisplayClass10_0`1.<<GetAsync>b__0>d.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

   at FiddlerBackendSDK.Core.Http.Client.AuthenticatedHttpClient.ExecuteWithValidTokenAsync(Func`1 action)

   at FiddlerBackendSDK.Core.Http.Client.AuthenticatedHttpClient.GetAsync[T](String requestUri, IFiddlerHttpStatusCodeValidator statusCodeValidator, IEnumerable`1 headers)

   at FiddlerBackendSDK.Core.Http.Client.AuthenticatedHttpClient.GetAsync[T](String requestUri, IFiddlerHttpStatusCodeValidator statusCodeValidator)

   at FiddlerBackendSDK.User.UserClient.GetCurrentUserAsync()

   at Fiddler.WebUi.Services.Backend.BackendService.SetUserInfo() in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 853

   at Fiddler.WebUi.Services.Backend.BackendService.<>c__DisplayClass47_0.<<Login>b__0>d.MoveNext() in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 468

--- End of stack trace from previous location where exception was thrown ---

   at Fiddler.WebUi.Services.Backend.BackendService.ExecuteWithSdkErrorsHandling(Func`1 action) in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 726

[2021-03-24 14:18:44:716] [Error] [NETCore] Failed to invoke hub method 'Login'.

Microsoft.AspNetCore.SignalR.HubException: Unexpected backend error.

   at Fiddler.WebUi.Services.Backend.BackendService.ExecuteWithSdkErrorsHandling(Func`1 action) in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 747

   at Fiddler.WebUi.Services.Backend.BackendService.Login(String apiUrl, String paymentUrl, String idToken) in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 431

   at Fiddler.WebUi.Services.Users.UsersService.Login(String apiUrl, String paymentUrl, String idToken, String userId, String[] oldUserIds, String userIdForSettings) in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Users\UsersService.cs:line 113

   at Fiddler.WebUi.Hubs.FiddlerHub.Login(String apiUrl, String paymentUrl, String idToken, String userId, String[] oldUserIds, String userIdForSettings) in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Hubs\FiddlerHub.Users.cs:line 17

   at Microsoft.AspNetCore.SignalR.Internal.DefaultHubDispatcher`1.ExecuteHubMethod(ObjectMethodExecutor methodExecutor, THub hub, Object[] arguments)

   at Microsoft.AspNetCore.SignalR.Internal.DefaultHubDispatcher`1.<>c__DisplayClass13_0.<<Invoke>g__ExecuteInvocation|0>d.MoveNext()

[2021-03-24 14:18:44:738] [Information] [Angular] Backend login failed.

[2021-03-24 14:18:44:743] [Error] [NETCore] Unexpected backend error.

System.NullReferenceException: Object reference not set to an instance of an object.

   at Fiddler.WebUi.Services.Backend.BackendService.<IsTrialAvailable>b__12_0() in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 49

   at Fiddler.WebUi.Services.Backend.BackendService.ExecuteWithSdkErrorsHandling[T](Func`1 action) in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 696

[2021-03-24 14:18:44:745] [Error] [NETCore] Failed to invoke hub method 'IsTrialAvailable'.

Microsoft.AspNetCore.SignalR.HubException: Unexpected backend error.

   at Fiddler.WebUi.Services.Backend.BackendService.ExecuteWithSdkErrorsHandling[T](Func`1 action) in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 718

   at Fiddler.WebUi.Services.Backend.BackendService.IsTrialAvailable() in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Services\Backend\BackendService.cs:line 47

   at Fiddler.WebUi.Hubs.FiddlerHub.IsTrialAvailable() in c:\Jenkins\workspace\fiddler-build-release-win\Fiddler\WebUi\Fiddler.WebUi\Hubs\FiddlerHub.License.cs:line 47

   at lambda_method(Closure , Object )

   at Microsoft.Extensions.Internal.ObjectMethodExecutorAwaitable.Awaiter.GetResult()

   at Microsoft.AspNetCore.SignalR.Internal.DefaultHubDispatcher`1.ExecuteHubMethod(ObjectMethodExecutor methodExecutor, THub hub, Object[] arguments)

   at Microsoft.AspNetCore.SignalR.Internal.DefaultHubDispatcher`1.<>c__DisplayClass13_0.<<Invoke>g__ExecuteInvocation|0>d.MoveNext()

[2021-03-24 14:18:44:874] [Error] [NETCore] Could not find file 'C:\Users\1013219\.fiddler\6731870c-dda0-4295-a31d-6e9dcf5373f0\Settings\appsettings.json'.

System.IO.FileNotFoundException: Could not find file 'C:\Users\1013219\.fiddler\6731870c-dda0-4295-a31d-6e9dcf5373f0\Settings\appsettings.json'.

Thanks for the quick update!

It seems that the errors are really the same as the ones in this thread: https://community.getfiddler.com/support/discussions/topics/12000026595

We are still investigating the issue, but could you try opening https://dashboard.getfiddler.com/ and sign in using the same user?

Fiddler Everywhere has a few network access requirements for `getfiddler.com` subdomains and missing some of them could lead to such errors.

I could not visit https://dashboard.getfiddler.com/ from the machine.

Even though with a fiddler account, have the same issue.

Could not reach https://dashboard.getfiddler.com/ from my machine.

Even though with a fiddler account, the same issue persist.

Thanks for the suggestions.

I have used the fiddler account but still the issue.

One more update. Regarding the network requirement, see

    https://login.getfiddler.com/ --- Yes
    https://api.getfiddler.com/ ---- Yes
    https://auth.getfiddler.com/ --- Yes
    https://amazonaws.com/ --- No