Calendar looks broken on single tour

Hi. I have updated to wordpress 5.6, I have installed jQuery Migrate Helper, but in tour single I have an error on console: GET https://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4-wp/themes/smoothness/jquery-ui.css?ver=2.0.1 net::ERR_ABORTED 404 and I have weird calendar after footer. If I hide path from \wp-content\plugins\travel-booking\travel-booking.php calendar doesn’t show. I have saved screenshot with error here: https://alisters-travel.com/wp-content/uploads/error.jpg
Regards,