TypeError thrown

Argument 2 passed to YachtFocus\YachtPresentation::getYachtByIdAndPostId() must be of the type int, null given, called in /var/www/vhosts/technieker.nl/domains/noorsesloepen.nl/public_html/wp-content/plugins/YachtFocus_yachtpresentation/src/YachtFocus/YachtPresentation.php on line 1213