The button stops working inside update panel

Question

When I use script manager and update panel with many buttons inside content template the buttons stop working even I used triggers tag 

 

 

please help

 <asp:ScriptManager ID="SecriptManager1" runat="server" />
      <asp:UpdatePanel ID="UpdatePanal1" runat="server" >
            <ContentTemplate>
.
.
.
.
.
 </ContentTemplate>
           <Triggers><asp:AsyncPostBackTrigger ControlID ="AddCourse" EventName="Click" />
              </Triggers>
      </asp:UpdatePanel>