Fatal error: Uncaught Error: Object of class WP_Error could not be converted to string
in /home/customer/www/editorialparaisoperdido.com/public_html/wp-content/themes/paraiso-perdido/single-libro.php on line 74

Call stack:

1. include()
   wp-includes/template-loader.php:106
2. require_once()
   wp-blog-header.php:19
3. require()
   index.php:17