WordPress can check for updates automatically, need to download and install new theme or plugin, license activation for premium plugin or theme, and etc.
When WordPress attempts to connect to Internet, but failed to do so as Internet is not available, the following error message may appear:
An unexpected error occurred. Something may be wrong with WordPress.org or this server’s configuration. If you continue to have problems, please try the support forums.
If your network uses proxy server to connect to Internet, WordPress has built-in API support for HTTP proxy. To add proxy server configuration to WordPress so that the outgoing HTTP connection made by WordPress is passed to proxy server, add the following constants and values to wp-config.php in the root of the WordPress installation.
In this example Wordpress is installed to var/www/html/blog so the command to edit this file would be:
sudo nano /var/www/html/blog/wp-config.php
Insert this near at the bottom of the file and then save the buffer......
/* Configure HTTP Proxy Server */
define('WP_PROXY_HOST', 'proxy.bears.cloud');
define('WP_PROXY_PORT', '3129');
define('WP_PROXY_USERNAME', '');
define('WP_PROXY_PASSWORD', '');
define('WP_PROXY_BYPASS_HOSTS', 'localhost');