Gridview checkbox disappeared

<pre><asp:GridView ID="GridView1" runat="server" ShowHeaderWhenEmpty="true" AutoGenerateColumns="False" BackColor="White" BorderColor="#CC9966" BorderStyle="None" BorderWidth="1px"  CellPadding="7" OnRowCommand="GridView1_RowCommand" >
            <HeaderStyle Width="10%" />
            <Columns>
                <asp:TemplateField HeaderText="Read ">
                    <ItemTemplate>
                       <asp:CheckBox runat="server" ID="CheckBoxRead" />
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="DateCreated" HeaderText="Date and Time" ItemStyle-Width="50%" ItemStyle-Wrap="false"  />
                <asp:BoundField DataField="ErrorTwo" HeaderText="Error" ItemStyle-Width="50%" ItemStyle-Wrap="false"  />
                <asp:TemplateField HeaderText="Receiver">
                    <ItemTemplate>
                       <asp:LinkButton runat="server" CommandArgument='<%# Eval("Sender") %>' Text='<%# Eval("Sender") %>'></asp:LinkButton> <%--OnClientClick="document.getElementById('id01').style.display='block'; return false"--%>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="Subject" HeaderText="Email Error" ItemStyle-Width="50%" ItemStyle-Wrap="false"  />
                
                <asp:TemplateField HeaderText="Email Body">
                    <ItemTemplate>
                       <asp:Button ID="txtItemBody"  runat="server" Text='<%# Eval("EmailHeader") %>' Width="100px" Enabled="false"/>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="View Email ">
                    <ItemTemplate>
                       <asp:Button runat="server"  CommandName="Select" CommandArgument="<%# Container.DataItemIndex %>" Text="View Email" />
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>

</asp:GridView>

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