WCF call with AJAX

I need to make the ajax call on an html page that will trigger a WCF application

WCF Contract

[ServiceContract]
public interface IMailingService
{
    [OperationContract]
    ServiceRetorno<string> ValidarParceiro(string login, string senha);
}

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class ControleMailingService : IMailingService
    {
        public ServiceRetorno<string> ValidarParceiro(string login, string senha)
        {

            ServiceRetorno<string> ret = new ServiceRetorno<string>();
            try
            {
                using (MailingData data = new MailingData())
                {
                    ret.Sucesso = data.ValidarParceiro(login, senha);
                    if (!ret.Sucesso)
                        ret.Mensagem = "Usuário ou senha inválido";
                    else
                        ret.DadosRetorno = CriarToken(login);
                }
            }
            catch(Exception ex)
            {
                ret.Sucesso = false;
                ret.Mensagem = "Falha ao validar login: " + ex.Message;
            }
            return ret;
        }
}

ENDPOINT CONFIGURATION

      <system.web>
    <compilation debug="true" targetFramework="4.0" />
  </system.web>
  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="MailingService_Endpoint" hostNameComparisonMode="StrongWildcard" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647">
          <readerQuotas maxDepth="32" maxStringContentLength="2147483647"
            maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" />
        </binding>
      </basicHttpBinding>
    </bindings>
    <services>
      <service name="WcfVisualFix.MailingService">
        <endpoint binding="basicHttpBinding" bindingConfiguration="MailingService_Endpoint"
          name="MailingService_Endpoint" contract="WcfVisualFix.IMailingService" />
        <endpoint binding="webHttpBinding" address="" 
          behaviorConfiguration="MailingServiceAjaxBehavior" contract="WcfVisualFix.IMailingService" />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
          <serviceMetadata httpGetEnabled="true" />
          <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
          <serviceDebug includeExceptionDetailInFaults="true" />
        </behavior>
      </serviceBehaviors>
      <endpointBehaviors>
        <behavior name="MailingServiceAjaxBehavior">
          <enableWebScript />
        </behavior>
      </endpointBehaviors>
    </behaviors>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" aspNetCompatibilityEnabled="false"  minFreeMemoryPercentageToActivateService="0" />

  </system.serviceModel>
  <system.webServer>
    <modules runAllManagedModulesForAllRequests="true" />
  </system.webServer>

AJAX CALL

$(document).ready(function(){

$("#btnAcessar").click(function(){

 $.ajax({
type: "POST",
url: "http://visualfix.dyndns-web.com:93/MailingService.svc/ValidarParceiro",
data: { "login" : $("#txtUsuario").val(), "senha": $("#txtSenha").val() },
contentType: 'application/json; charset=utf-8',
dataType: "json",
success: 
 function (res) {
if(res.Sucesso)
 $("#txtToken").val(res.DadosRetorno);
else
 $("#txtToken").val(res.Mensagem);
 },
error: 
 function (err) {
alert(err.responseJSON);
 }
 });

});
});

The call returns error statusCode 0.

XMLHttpRequest can not load link . Response to preflight request does not pass access control check: In 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access. The response had HTTP status code 400.

Testing through SOAP UI works correctly.