WCF The Security Support Provider Interface (SSPI) negotiation failed

I am using a wcf service that I created, when both hosting machine and the client machine are on the same domain everything works just fine. When I publish the client app to the webserver in the DMZ I am getting the following error:

SOAP security negotiation with 'http://10.0.0.14:3790/Bullfrog/QBService/QBService' for   
target 'http://10.0.0.14:3790/Bullfrog/QBService/QBService' failed. See inner exception  
for more details.The Security Support Provider Interface (SSPI) negotiation failed.

Here is my service main where I set up the service

      Uri baseAddress = new Uri("Http://10.0.0.14:3790/Bullfrog/QBService");
      ServiceHost selfHost = new ServiceHost(typeof(QBService), baseAddress);

            try
            {
                selfHost.AddServiceEndpoint(
                    typeof(IQBService),
                    new WSHttpBinding(),
                    "QBService");

                ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
                smb.HttpGetEnabled = true;
                selfHost.Description.Behaviors.Add(smb);
                selfHost.Open();

                Console.WriteLine("The service is ready");


            }
            catch (CommunicationException ce)
            {
                //log.Error(ce.Message, ce);
                Console.WriteLine(ce.Message, ce);
                selfHost.Abort();
            }

and here is the config section on my client

  <system.serviceModel>
<bindings>
  <wsHttpBinding>
    <binding name="WSHttpBinding_IQBService" closeTimeout="00:01:00"
        openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
        bypassProxyOnLocal="false" transactionFlow="false" hostNameComparisonMode="StrongWildcard"
        maxBufferPoolSize="524288" maxReceivedMessageSize="65536"
        messageEncoding="Text" textEncoding="utf-8" useDefaultWebProxy="true"
        allowCookies="false">
      <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
          maxBytesPerRead="4096" maxNameTableCharCount="16384" />
      <reliableSession ordered="true" inactivityTimeout="00:10:00"
          enabled="false" />
      <security mode="Message">
        <transport clientCredentialType="Windows" proxyCredentialType="None"
            realm="" />
        <message clientCredentialType="Windows" negotiateServiceCredential="true"
            algorithmSuite="Default" />
      </security>
    </binding>
  </wsHttpBinding>
</bindings>
<client>
  <endpoint address="http://10.0.0.14:3790/Bullfrog/QBService/QBService"
      binding="wsHttpBinding" bindingConfiguration="WSHttpBinding_IQBService"
      contract="IQBService" name="WSHttpBinding_IQBService">
    <identity>
      <userPrincipalName value="Administrator@bullfrogspas.local" />
    </identity>
  </endpoint>
</client>

I am sure the problem is because it is using windows authentication. Any Ideas? Thank You!