error: wp-admin/includes/translation-install.php on line 59

Solution:

In my case it was the proxy blocking the communication with WordPress server.

I fixed it by following this guide.

Basically I had to define these rules into wp-config.php:

/* Configure proxy Server */
define('WP_PROXY_HOST', 'x.x.x.x');
define('WP_PROXY_PORT', '8080');
define('WP_PROXY_USERNAME', '');
define('WP_PROXY_PASSWORD', '');
define('WP_PROXY_BYPASS_HOSTS', 'localhost');