Unable to update and retrieve error messages if I would nested my gridview inside of UpdatePanel?

I can still able to delete my data though, but unfortunately I was unable to update and retrieve error messages if empty field is submitted on my search box.

Any idea how do I resolve this error?

Here's my code for it

<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager><asp:UpdatePanel ID="UpdatePanel1" runat="server">><ContentTemplate><asp:Label ID="lblOrderError" runat="server" ForeColor="Red"></asp:Label></p><label>Search:</label><input class="adminStylized" type="text" name="searchRecord" ID="txtSearchOrder" runat="server" placeholder="Order number" /><button ID="btnSearchOrder" runat="server" onServerClick="SearchOrder">Search</button><br /><br /><hr /><asp:GridView ID="grdOrder" runat="server" AutoGenerateColumns="False"
                        DataKeyNames="orderID" onrowcancelingedit="grdOrder_RowCancelingEdit"
                        onrowediting="grdOrder_RowEditing" onrowupdating="grdOrder_RowUpdating"
                        onrowdeleting="grdOrder_RowDeleting"><Columns><asp:BoundField DataField="orderID" HeaderText="Order ID"
                                SortExpression="orderID" ReadOnly="true"/><asp:BoundField DataField="username" HeaderText="Username"
                                SortExpression="username" ReadOnly="true"/><asp:TemplateField HeaderText="Game Title" SortExpression="title"><EditItemTemplate><asp:DropDownList ID="ddlOrderTitle" runat="server"
                                        DataSourceID="SqlDataSource1" DataTextField="title" DataValueField="title" SelectedValue='<%# Eval("title") %>'></asp:DropDownList><asp:SqlDataSource ID="SqlDataSource1" runat="server"
                                        ConnectionString="<%$ ConnectionStrings:GameConnectionString %>"
                                        SelectCommand="SELECT [title] FROM [games]"></asp:SqlDataSource></EditItemTemplate><ItemTemplate><asp:Label ID="lblOrderTitle" runat="server" Text='<%# Bind("title") %>'></asp:Label></ItemTemplate></asp:TemplateField><asp:TemplateField HeaderText="Quantity" SortExpression="quantity"><EditItemTemplate><asp:TextBox ID="txtOrderQuantity" runat="server" Text='<%# Bind("quantity") %>'></asp:TextBox></EditItemTemplate><ItemTemplate><asp:Label ID="lblOrderQuantity" runat="server" Text='<%# Bind("quantity") %>'></asp:Label></ItemTemplate></asp:TemplateField><asp:CommandField ShowEditButton="True" /><asp:TemplateField ShowHeader="False"><ItemTemplate><asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False"
                                        CommandName="Delete" Text="Delete" OnClientClick="javascript : return confirm('Confirm delete this order record?');"></asp:LinkButton></ItemTemplate></asp:TemplateField></Columns></asp:GridView></ContentTemplate></asp:UpdatePanel>