Traefik is a modern reverse proxy that not enables the use of your subdomains, but has the ability to provide authentication and issue SSL certificate using Lets Encrypt.
WARNING: Port 80 and 443 have to be open for Traefik to work. By default, your ports should work. If you have Caddy, CPanel, or some server website hosting software installed; you WILL have problems. Without Traefik being able to route through 80 and 443, your certificates will not work!