调用WCF服务时，“调用者未通过服务进行身份验证”异常？

Question

我有一个调用WCF服务的网络应用程序 问题是，对于某些用户，我得到The caller was not authenticated by the service的例外，而对其他用户则有效。我无法弄清楚为什么会有区别。我想补充一点，我使用的是Windows身份验证。

我的代码是：

binding = new WSHttpBinding(SecurityMode.Message);
binding.Security.Message.ClientCredentialType = MessageCredentialType.Windows;
binding.Security.Message.NegotiateServiceCredential = true;
binding.Security.Message.EstablishSecurityContext = false;

// create the channel factory for the service proxy
factory = new ChannelFactory<IWCF>(
    binding,
    new EndpointAddress(
        new Uri( 
          CriptographyService.Decrypt( 
            ConfigurationSettings.AppSettings["WCF"] 
          ) 
        ),
        EndpointIdentity.CreateUpnIdentity( 
          CriptographyService.Decrypt( 
            ConfigurationSettings.AppSettings["Identity"]
          ) 
        ) 
    ) 
 );

factory.Credentials.Windows.AllowedImpersonationLevel =
  TokenImpersonationLevel.Delegation;

// create a channel to the service
return factory.CreateChannel();