Hi,
Thanks for the site URL. The “Advance Search” page is missing on your website. Please check at Dashboard – Pages, may be it was deleted. If it is deleted you can create a new one, Go to Pages -> Add New, add the title “Advance Search” and select the Template “Advance Search”. Publish the page and then check the search on the front end. You can check this for reference https://screenrec.com/share/mkWnwaUyd7.
Please try and let us know.
Thanks