One common error is themes loading the incorrect version of jQuery
ubermenu.min.js via the wp_enqueue_scripts hook, and loads in your footer. If you theme does not include the standard wp_footer() hook in its
footer.php, then this script can’t load.
Solution: Add the wp_footer() hook to your theme. Any professional theme should already have this hook present.
Solution: Locate the script causing the issue, and either resolve the error or exclude it from the minification/concatenation process.