I'm using this plugin with my Wordpress site and it works fine https://wordpress.org/plugins/auto-install-free-ssl/
This is also available as standalone application, no need for wordpress
If your web hosting control panel (e.g., cPanel) has SSL installation feature enabled, you can install the SSL certificate on YourDomain.com easily.
Otherwise, contact your web hosting provider to install the SSL certificate for you.
Is there a plugin for Woltlab that will automatically install and renew a free SSL certificate from Let's Encrypt?
Let's Encrypt ssl
The certificate was issued by Let's Encrypt.