wiwimaster

Not true, there is another way (had to find it myself):

//Adjust wordpress
add_filter( ‘post_link_category’, ‘remove_child_categories_from_permalinks’ );
function remove_child_categories_from_permalinks( $category ) {
// source: https://wordpress.stackexchange.com/questions/147453/remove-child-category-from-url
while ( $category->parent ) {
$category = get_term( $category->parent, ‘category’ );
}

return $category;
}

//Adjust Yoast SEO:
add_filter( ‘get_post_metadata’, ‘my_filter_primary_category’, 20, 4 );
function my_filter_primary_category( $check, $object_id, $meta_key, $single ) {
// source: https://github.com/Yoast/wordpress-seo/issues/6184
if ( $meta_key === ‘_yoast_wpseo_primary_category’ ) {
return $single ? false : array();
}

return $check;
}

Thanks devnihil, great advice to use WP Health, this helped me to find the issue – it is indeed caused by another plugin, WP Ultimate Recipe. Yoast worked fine without the plugin.

thanks
Jan

good catch. I’ve added the media folder to the ones being watched, and now also the folder “wp-content/cache/adaptive-images” got created. However I’ve called a few pages ith ~400px wide browser, but no images were created in the cache folder, and all of a sudden only empty image frames appear.

would you mind having another look?
thanks
Jan