使用Azure Active Directory执行身份验证时发生Authentication_UI_failed异常

Question

我正在使用Windows Phone 8.1应用程序，并希望通过Azure Active Directory身份验证对访问后端Web Api的用户进行身份验证。我已经参考了Git Hub示例（https://github.com/Azure-Samples/active-directory-dotnet-windowsphone-8.1），当在按钮的onclick事件上编写以下代码时，示例对我来说很好用

      AuthenticationResult result = await authContext.AcquireTokenSilentAsync(todoListResourceId, clientId);
         if (result != null && result.Status == AuthenticationStatus.Success)
         {
             // A token was successfully retrieved. Post the new To Do item
             AddTodo(result);
         }
         else
         {

             authContext.AcquireTokenAndContinue(todoListResourceId, clientId, redirectURI, AddTodo);
         }

但是，当我在异步函数中编写它并在主页面中调用它时，它会抛出以下异常。

{Microsoft.IdentityModel.Clients.ActiveDirectory.AdalException: authentication_ui_failed: The browser based authentication dialog failed to complete ---> System.Exception: The remote procedure call failed. (Exception from HRESULT: 0x800706BE)
   at Windows.Security.Authentication.Web.WebAuthenticationBroker.AuthenticateAndContinue(Uri requestUri, Uri callbackUri, ValueSet continuationData, WebAuthenticationOptions options)
   at Microsoft.IdentityModel.Clients.ActiveDirectory.WebUI.Authenticate(Uri authorizationUri, Uri redirectUri, IDictionary`2 headersMap, CallState callState)
   --- End of inner exception stack trace ---
   at Microsoft.IdentityModel.Clients.ActiveDirectory.WebUI.Authenticate(Uri authorizationUri, Uri redirectUri, IDictionary`2 headersMap, CallState callState)
   at Microsoft.IdentityModel.Clients.ActiveDirectory.AcquireTokenInteractiveHandler.AcquireAuthorization()
   at Microsoft.IdentityModel.Clients.ActiveDirectory.AuthenticationContext.AcquireTokenAndContinueCommon(String resource, String clientId, Uri redirectUri, UserIdentifier userId, String extraQueryParameters, AuthenticationContextDelegate authDelegate)
   at Microsoft.IdentityModel.Clients.ActiveDirectory.AuthenticationContext.AcquireTokenAndContinue(String resource, String clientId, Uri redirectUri, AuthenticationContextDelegate authDelegate)
   at TodoListClient.MainPage.<MainPageAfterLoad>d__0.MoveNext()
    ErrorCode: authentication_ui_failed}``

我也尝试将此代码添加到main_Loaded函数中，但没有帮助。