asp.net button click event not firing on web server

Question

i know it's a simple problem, i searched alot but couldn't find a solution
i have this button in aspx page:

<asp:Button runat="server" ID="btnSubmit" Text="Submit" OnClick="btnSubmit_Click" CssClass="btn"/>

the button works fine on my local machine. it writes to DB an email from textbox.
when i upload my webform to the server, the button refreshes the page but the event not firing.

please note: by button inside a div and it's hidden until a radio button is checked.

Thank you

Answer 1

i found the issue. i tried to read (not write) to see if i have a connection problem. The error i had solved in this link Login failed for user 'IIS APPPOOL\\ASP.NET v4.0' and this solved my problem.

i hope this may help any one will have the same problem.

Thanks for all your help.