error with smush it.... Site went down

Site went down: 500 error. Server not down. Was working with plugins. This is in the error log

PHP Fatal error: Cannot redeclare i18n() (previously declared in /d1/users/Sitename/public_html/wp-content/plugins/wp-smush-pro/wp-smush.php:275) in /d1/users/Sitename/public_html/wp-content/plugins/wp-smushit/wp-smush.php on line 280