Once in a while, I need to disconnect and then reconnect iThemes Sync because of a problem. This can be a problem if the Sync dashboard shows ‘Site Down’ and you can not see the plugin in the WordPress admin because it is set to hidden. The following snippet will temporarily force the plugin to show in the WordPress admin for you to reconnect. Enter the url into your browser url bar.
http://yoursite.com/wp-admin/plugins.php?ithemes-sync-force-display=1