TypeError thrown

SlimSEO\Breadcrumbs::add_post_type_archive_link(): Argument #1 ($post_type) must be of type string, null given, called in /var/www/vhosts/clauswunsch.com/httpdocs/dirndldienstag.at/wp-content/plugins/slim-seo/src/Breadcrumbs.php on line 122