I have noticed that console has some errors on page load.
One of them contains multiple “#user_login” IDs and the other contains multiple “#wp-submit” IDs.
File that causes that can be found in “/gillion/inc/templates/login_popup.php”, but if I tried to change any of them, the login and register does not work anymore.
Your theme does not have any function that would do anything containing “user-login” or “wp-submit”.
Could you check that please?
Kind regards, Tim