ASP.NET 4.6 Conversion failed when converting the varchar value 'YES' to data type int

Question

Please help as this is a time sensitive issue I'm having with a project. The problem is that I have a GridView and in that GridView I have one column that requires a 'YES' or 'NO' response. I'm using a dropdownlist in the EditItemTemplate to grab distinct or unique choices from the database. Everything loads and displays fine from the datasource as you can see in this picture:

When I click the edit button the fields display appropriately as well as you can see from this picture:

However, when I select either 'YES' or 'NO', and click Update; I get the following error:

Here is the snippet of my .aspx code

<asp:TemplateField HeaderText="Required" SortExpression="IsRequired">
                <EditItemTemplate>
                    <asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="True" DataSourceID="dsIsRequiredDDL" DataTextField="IsRequired" DataValueField="IsRequired"></asp:DropDownList>
                    <asp:SqlDataSource ID="dsIsRequiredDDL" runat="server" ConnectionString="<%$ ConnectionStrings:BITSDevConnectionString %>" SelectCommand="SELECT DISTINCT [IsRequired] FROM [EmpCertType]"></asp:SqlDataSource>
                </EditItemTemplate>
                <ItemTemplate>
                    <asp:Label ID="Label1" runat="server" Text='<%# Bind("IsRequired") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>

And he is a picture of the table in my database:

For the record, all data in the database is test (fictitious) data so there are no PII concerns.

So the questions are: What is going on? Why am I getting this error? And most importantly, how do I correct this?

I've tried using a radiobuttonlist and got an error with that as well. I've tried hard coding the selections in the dropdownlist and got the same error I got here, and I've done hours and hours of research on this one problem alone.

Any and all help is greatly appreciated!