Omit custom post type from wp-sitemap.xml based on meta key using wp_sitemaps_posts_query_args
The error happens because the filter callback (shapeSpace_disable_sitemap_post_meta()) expects to receive two parameters ($args and $post_type) and yet you call add_filter() without setting the fourth parameter to 2. So to solve the problem: // Replace this: add_filter(‘wp_sitemaps_posts_query_args’, ‘shapeSpace_disable_sitemap_post_meta’); // with this one: add_filter(‘wp_sitemaps_posts_query_args’, ‘shapeSpace_disable_sitemap_post_meta’, 10, 2);