PHPMailer error

I get this error when trying to send a test e-mail

Fatal error: Uncaught Error: Class ‘PHPMailer’ not found in /wp-content/plugins/easy-wp-smtp/easy-wp-smtp.php:238 Stack trace: #0 /wp-content/plugins/easy-wp-smtp/easy-wp-smtp-admin-menu.php(166): swpsmtp_test_mail(‘REDACTED’, ‘Test’, ‘test’) #1 /wp-includes/class-wp-hook.php(286): swpsmtp_settings(”) #2 /wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(”, Array) #3 /wp-includes/plugin.php(453): WP_Hook->do_action(Array) #4 /wp-admin/admin.php(224): do_action(‘settings_page_s…’) #5 /wp-admin/options-general.php(10): require_once(‘REDACTED’) #6 {main} thrown in /wp-content/plugins/easy-wp-smtp/easy-wp-smtp.php on line 238