Load on demand not working

[Steve]

The load on demand for the combobox is not working once I move the page to the shared host. It works fine while testing it in Visual Studio.
Up on the shared host, when I click on the combobox, it drops down showing the items in the box. But, as soon as I type a single letter, the "Loading..." message appears and it just sits there. Even if I type the first letter of the first item in the box, it will show the loading message and then do nothing.

I tried both loading from server side, and also by setting the EnableAutomaticLoadOnDemand="true". The latter doesn't even load the list.

This will at least display the list:

<telerik:RadComboBox ID="CustomerSearch" runat="server" Width="180" Height="160"
    MarkFirstMatch="true"  AllowCustomText="true" CssClass="CustomerSearch"
    EnableLoadOnDemand="true" EnableVirtualScrolling="true" OnItemsRequested="CustomerSearch_ItemsRequested"
     OnClientSelectedIndexChanged="searchnav" EmptyMessage="Select a customer" DataSourceID="dsCustomer" DataTextField="CustomerName"
    DataValueField="NavPath" BackColor="White" Skin="Forest" />

<asp:SqlDataSource ID="dsCustomer" runat="server"
    SelectCommand="CustomerSearchName" SelectCommandType="StoredProcedure">
</asp:SqlDataSource>


<telerik:RadScriptBlock ID="RadScriptBlock1" runat="server">
    <script type="text/javascript">
        function searchnav(sender, args) {
            var iframe = document.getElementById('ctl00_iMainPages');
            iframe.src = sender.get_value();
        }

    </script>
</telerik:RadScriptBlock>

This is the code-behind:

Protected Sub CustomerSearch_ItemsRequested(sender As Object, e As RadComboBoxItemsRequestedEventArgs)
    Dim dal As New Customer

    Dim data As DataTable = dal.CustomerSearchName(Session("StoreID"), e.Text).Tables(0)

    Dim itemOffset As Integer = e.NumberOfItems
    Dim endOffset As Integer = Math.Min(itemOffset + 10, data.Rows.Count)
    e.EndOfItems = endOffset = data.Rows.Count

    For i As Integer = itemOffset To endOffset - 1
        CustomerSearch.Items.Add(New RadComboBoxItem(data.Rows(i)("CustomerName").ToString(), data.Rows(i)("NavPath").ToString()))
    Next

    e.Message = GetStatusMessage(endOffset, data.Rows.Count)
End Sub
Private Shared Function GetStatusMessage(ByVal offset As Integer, ByVal total As Integer) As String
    If total <= 0 Then
        Return "No matches"
    End If

    Return [String].Format("Items <b>1</b>-<b>{0}</b> out of <b>{1}</b>", offset, total)
End Function

[Dimitar Terziev]

Hello Steve,

If the control is not populated after the request for items is initiated, the most common reason is a server error during the item retrieval. Could you check for errors using the developer tools of the browser that you are using?

Regards,
Dimitar Terziev
Telerik

[Steve]

How do I check for errors using the developer tools of the browser? I'm currently using Firefox, as IE 11 is not working properly for me (I have a ticket open for that).

When I click on the dropdown combobox initially, it is loaded with the data. It's the load on demand, I believe that is not working for some reason.  That is server side, obviously. So how do I troubleshoot that on a hosted server? It's working fine in my local development environment.