PHP error: Class Helper not found

Fatal error: Uncaught Error: Class "MR\FeatureFlags\Helper\Helper" not found
in /var/www/wp-content/plugins/feature-flags/includes/Flag.php on line 41

Call stack:

MR\FeatureFlags\Flag::is_enabled()
wp-content/themes/devtheme/inc/custom-post-types.php:2
require()
wp-content/themes/devtheme/functions.php:408
include()
wp-settings.php:591
require_once()
wp-config.php:71
require_once()
wp-load.php:50
require_once()
wp-admin/admin.php:34
require_once()
wp-admin/network/admin.php:13
require_once()
wp-admin/network/plugins.php:11

The plugin works fine on my local environment, but does not load on the service provider’s servers. It seems that the file ‘feature-flags/includes/helper/Helper.php’ isn’t invoked anywhere in the codes. As a workaround, I have modified the plugin.php file to load the helper.php file:

if ( ! file_exists( Flag::class ) ) {
	include_once __DIR__ . '/vendor/autoload.php';
	require_once( __DIR__ . '/includes/helper/Helper.php');
}