Filter just keeps saying Loading

Question

We use Ext.Net runtime version 4.0.30319. In one of our environment, when we try to filter the values in columns Broker or Custodian, it just keeps saying Loading, and the list of Broker or Custodian never comes up. The same code works in another environment (the list of Broker or Custodian shows up).

Why in that 1 environment, the list doesn't show up, instead it just keeps saying Loading ? Thank you.

Here are the codes.

X.Viewport().Layout(LayoutType.Fit).Items(
X.TabPanel().ID("ArchiveTabPanel")
.Items(
        X.GridPanel().ID("GridPanel1").MarginSpec("1 1 1 1").Cls("cust-grid").Title("Archive Trade Tickets").Icon(Icon.ServerCompressed)
                    .Bin(
                            X.StoreForModel().ID("Store2").Parameters(p => p.Add(new StoreParameter("id", "App.HiddenId.getValue()", ParameterMode.Raw)))
                            .Proxy(X.AjaxProxy()
                            .Url(Url.Action("GetFilterCustodian"))
                            .Reader(Html.X().JsonReader().RootProperty("data"))
                            ).Sorters("value", Ext.Net.SortDirection.ASC)
                            , X.StoreFor<OurCompany.OurApp.Model.vTRADETICKET>().ID("Store3").Parameters(p => p.Add(new StoreParameter("id", "App.HiddenId.getValue()", ParameterMode.Raw)))
                                .Proxy(X.AjaxProxy()
                                .Url(Url.Action("GetFilterBroker"))
                                .Reader(Html.X().JsonReader().RootProperty("data"))
                               ).Sorters("value", Ext.Net.SortDirection.ASC)
                    )

               .Store(X.StoreForModel().ID("Store1")
                        .Parameters(p => p.Add(new StoreParameter("id", "App.TradeDate.getValue()", ParameterMode.Raw)))
                    .Proxy(X.AjaxProxy()
                            .Url(Url.Action("ReadData"))
                        .Reader(X.JsonReader().RootProperty("data"))
                )
                .RemoteSort(false).Sorters("perform_File_TimeStamp", Ext.Net.SortDirection.DESC)
                .RemotePaging(false).PageSize(10000)
                )

                .Listeners(ls =>
                {
                    ls.ItemContextMenu.Fn = "showMenu";
                    ls.ItemContextMenu.StopEvent = true;
                })

                .ColumnModel(
                X.Column().Text("BatchId").DataIndex("Perform_File_TimeStamp").Width(60).Hideable(false).Groupable(false).Align(Alignment.Center).Filter(X.StringFilter()),
                X.Column().Text("Match").ID("allocation_Match").DataIndex("Allocation_Match").Width(50).Align(Alignment.Center).Hideable(false).Groupable(false).Filter(X.ListFilter().Options("Yes,No")),

               X.Column().Text("Comments").DataIndex("Comments").Width(80).Hideable(false).Groupable(false).Filter(X.StringFilter()),

       X.Column().Text("Broker").DataIndex("Broker").Width(200).Hideable(false).Groupable(false).Filter(X.ListFilter().DataIndex("Broker").StoreID("Store3").LabelField("Value").IDField("Value")),
                X.Column().Text("Custodian").DataIndex("Custodian").Width(150).Hideable(false).Groupable(false).Filter(X.ListFilter().DataIndex("Custodian").StoreID("Store2").LabelField("Value").IDField("Value")),

                X.Column().Text("Primary Contact").DataIndex("Primary_Contact").Width(150).Hideable(false).Groupable(false).Filter(X.StringFilter()),
                X.Column().Text("Main Phone").DataIndex("Main_Phone").Width(95).Hideable(false).Groupable(false).Filter(X.StringFilter()).Align(Alignment.Center),
                X.Column().Text("Phone").DataIndex("Phone").Width(95).Hideable(false).Groupable(false).Filter(X.StringFilter()).Align(Alignment.Center),
                X.Column().Text("By").DataIndex("Maintained_By").Width(80).Hideable(false).Groupable(false).Filter(X.StringFilter()).Align(Alignment.Center)
        )