The directory /blog/trekking-laurino-alla-grava-vesalo-laurino/trekking-da-laurino-alla-grava-di-vesalo-2018-cilento-outdoor/ does not contain an index file.
You have to create a page called index.html, index.htm or index.php (lower case).
Warning: if you have just activated your site you might have to wait up to 24 hours before it is visible.