Cannot start session without errors, please check errors given in your PHP and/or webserver log file and configure your PHP installation properly.
====== Solusinya? ======
sudo chown nginx:nginx /var/lib/php/session -R
sudo chmod 0777 /var/lib/php/session
dan pastikan
nano /etc/php.ini
nilainya sesuai ini
session.save_path = "/var/lib/php/session"