We were able to fix the problem. It was giving the error in the console: “Uncaught ReferenceError: buse_site_users is not defined”.
This line of code below in the admin.groups.php file not loading that caused the issue:
wp_enqueue_script( ‘buse-site-users’, admin_url( ‘admin-ajax.php?action=buse_site_users_script’ ), array(), null );
So we added some codes after that to fix it:
wp_localize_script( ‘group-editor’, ‘buse_site_users’, $current_site_all_users);