After installing OAuth Client plugin, if you have proxy setup and if it is not enabled then you get this error. To resolve it, you have to enable proxy by adding following lines to wp-config.php file
define(‘WP_PROXY_HOST’, ‘<proxy-server-url>’);
define(‘WP_PROXY_PORT’, ’<proxy-server-port>’);
define(‘WP_PROXY_USERNAME’, ‘<proxy-server-username>’);
define(‘WP_PROXY_PASSWORD’, ‘<proxy-server-password>’);
After setup, please download the plugin. If you still face the same issue, please write us on info@miniorange.com