This is not a fatal error. This error simply says, it was unable to contact the server to check whether the plugin has an updated version. This could be because the server was down or was under maintenance when your site checked for updates.
If the issue persists after 24 hours, please contact the author of the plugin giving you this issue. From the code you posted, it looks like the plugin is ‘symple-shortcodes’ and the URL it is trying to contact is ‘http://wp-updates.com/api/2/plugin’.