Sticky header stopped working

Hello! I noticed that my sticky header stopped working. Can you see what could be the problem?
https://birdclick.co.uk/endonet/

Thanks

I have been trying to figure out what is breaking the sticky header. Once again I feel like I don't understand the fix I stumbled across!

I took the broken page:
https://birdclick.co.uk/endonet/about-endonet_broke.php
and pasted the content into a working page leaving the header and footer as they were. Now sticky header works again!
https://birdclick.co.uk/endonet/about-endonet.php

Looking at the code i cannot see any errors or difference in the content TBH! If you can show me what could be causing my sticky header to break I would be very curious and please to find out!

Rob

I figured it out! please close this ticket. I had left the last few lines of code on the 'footer.php' and they needed to be at the end of the page that is calling the .php content. Incase it helps this is the code that i moved from 'footer.php' to the page calling the footer:

<!-- #content end -->

<?php include("footer.php"); ?>
</div>
<!-- #wrapper end -->

<!-- Go To Top
============================================= -->
<div id="gotoTop" class="icon-angle-up"></div>

<!-- JavaScripts
============================================= -->
<script src="js/jquery.js"></script>
<script src="js/plugins.min.js"></script>

<!-- Footer Scripts
============================================= -->
<script src="js/functions.js"></script>
</body>
</html>