Renew Let's Encrypt SSL Lightsail Subdomain

Hello,

I have used these instructions in the past, and was able to get it to work: Tutorial: Using Let’s Encrypt SSL certificates with your LAMP instance in Amazon Lightsail

However I am not able to Secure my subdomain, which hosts a client app. The parent level domain, no longer points to anything and only the subdomain is in use. I use to be able to just renew the subdomain on the server the the subdomain points to.

The only thing I am changing from the instructions above is removing reference to the WILDCARD variable. Again I just need to the Subdomain renewed.

Thanks, and hope someone can point me in the right direction.