linkbutton not firing the onclick handler and does not do a post back for the page

Question

I have a user control and have a link button in it with onclick property but whenever i click this linkbutton nothing happened no postback for the page or firing the handler

I have added the causevalidation to false and add the validationgroup as well with no success like this:

<asp:LinkButton runat="server" ID="Approve" OnClick="Approve_Click" CauseValidation="false" ValidationGroup="approve"/>

any help Please i have been Searching about this issue 2 days with no success