[SOLVED] WSDualHttpBinding in WPF not responding

I have problem with using WCF WSDualHttpBinding only in WPF application. Before changes this WCF worked. Now not working. I changed only ServiceBehaviour (ConcurrencyMode and InstanceContextMode) to:

[ServiceBehavior(IncludeExceptionDetailInFaults = true, ConcurrencyMode = ConcurrencyMode.Reentrant, InstanceContextMode = InstanceContextMode.PerSession)]

After that, WCF not responding, see exception detail. Any ideas?

System.Reflection.TargetInvocationException was unhandled by user code
  HResult=-2146232828
  Message=An exception occurred during the operation, making the result invalid.  Check InnerException for exception details.
  Source=System
  StackTrace:
       at System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary()
       at MainModuleTracking.GXService.GetServerItemsCompletedEventArgs.get_Result() in d:\Projects\!New!\GXClient\MainModuleTracking.Desktop\Service References\GXService\Reference.cs:line 6274
       at Main.ViewModels.LogOnWindowViewModel.BaseFW_OnGetServerItemsCompleted(Object sender, GetServerItemsCompletedEventArgs e) in d:\Projects\!New!\GXClient\Main.Silverlight\ViewModels\LogOnWindowViewModel.cs:line 208
       at MainModuleTracking.GXService.MainServiceClient.OnGetServerItemsCompleted(Object state) in d:\Projects\!New!\GXClient\MainModuleTracking.Desktop\Service References\GXService\Reference.cs:line 8818
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.DispatcherOperation.InvokeImpl()
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Windows.Threading.DispatcherOperation.Invoke()
       at System.Windows.Threading.Dispatcher.ProcessQueue()
       at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
       at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
       at System.Windows.Window.ShowHelper(Object booleanBox)
       at System.Windows.Window.ShowDialog()
  InnerException: System.TimeoutException
       HResult=-2146233083
       Message=Opening the http://192.168.7.104:8181/WpfMainService channel timed out after 00:01:00. The time allotted to this operation may have been a portion of a longer timeout.
       Source=mscorlib
       StackTrace:
         Server stack trace:
            at System.Runtime.AsyncResult.End[TAsyncResult](IAsyncResult result)
            at System.ServiceModel.Channels.ServiceChannel.SendAsyncResult.End(SendAsyncResult result)
            at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result)
            at System.ServiceModel.Channels.ServiceChannelProxy.InvokeEndService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
            at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)
         Exception rethrown at [0]:
            at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
            at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
            at MainModuleTracking.GXService.IMainService.EndGetServerItems(IAsyncResult result)
            at MainModuleTracking.GXService.MainServiceClient.EndGetServerItems(IAsyncResult result) in d:\Projects\!New!\GXClient\MainModuleTracking.Desktop\Service References\GXService\Reference.cs:line 8802
            at MainModuleTracking.GXService.MainServiceClient.OnEndGetServerItems(IAsyncResult result) in d:\Projects\!New!\GXClient\MainModuleTracking.Desktop\Service References\GXService\Reference.cs:line 8810
            at System.ServiceModel.ClientBase`1.OnAsyncCallCompleted(IAsyncResult result)
       InnerException:

EDIT

callbackService = new ServiceCallback();
InstanceContext context = new InstanceContext(callbackService);
mainService = new MainServiceClient(context, "WSDualHttpBinding_IMainService");
mainService.SubscribeErrorsAsync();
mainService.GetServerItemsAsync();