Can not activate plugin (Digital Ocean)

Recently I moved to Digital Ocean and I’m using AuthorH Review pro version.
But in digital ocean I can not activate the plugin. This is the error

Fatal error: Uncaught Error: Call to undefined function ereg_replace() in /var/www/html/wp-content/plugins/wp-reviews/inc/admin/settings.php:243 Stack trace: #0 /var/www/html/wp-content/plugins/wp-reviews/inc/admin/settings.php(15): WPR_LK_CleanTheDomain('https://www.geek...') #1 /var/www/html/wp-content/plugins/wp-reviews/wp-reviews.php(55): require_once('/var/www/html/w...') #2 /var/www/html/wp-admin/includes/plugin.php(1882): include('/var/www/html/w...') #3 /var/www/html/wp-admin/plugins.php(164): plugin_sandbox_scrape('wp-reviews/wp-r...') #4 {main} thrown in /var/www/html/wp-content/plugins/wp-reviews/inc/admin/settings.php on line 243