A little sample of the service hosted
#region hosting the service 

      Uri baseAddress = new Uri("http://127.0.0.1:18080/MyDaemon"); 
      string address = "http://127.0.0.1:18080/MyDaemon"; 

      using (ServiceHost host = new ServiceHost(typeof(CommunicatorServices), baseAddress)) 
      { 
        BasicHttpBinding binding = new BasicHttpBinding(BasicHttpSecurityMode.None); 
        host.AddServiceEndpoint(typeof(ICommunicatorServices), binding, address); 

        ServiceMetadataBehavior serviceMetadataBehavior = host.Description.Behaviors.Find<ServiceMetadataBehavior>(); 

        if (serviceMetadataBehavior == null) 
        { 
          serviceMetadataBehavior = new ServiceMetadataBehavior(); 
          host.Description.Behaviors.Add(serviceMetadataBehavior); 
        } 
        host.AddServiceEndpoint(typeof(IMetadataExchange), MetadataExchangeBindings.CreateMexHttpBinding(), "http://127.0.0.1:18080/MyDaemon/mex"); 

        host.Open(); 
        Console.WriteLine("Service is running....press any key to terminate."); 
        Console.ReadKey(); 
        host.Close(); 
#endregion

You're using 2.6, which still had a lot of issues that have been already fixed (including some with related to wrong web response). Try git head instead and see if it's still there.