Let’s Encrypt: Service that allows users to get website SSL certificates for free.

Once the server receives it, it’ll use its private key to decrypt it.
The browser and server can now form an encrypted connection to safely transfer information.
Both paid and free SSL certificates provide strong encryption for securely connecting your site and its visitors.
Once you have installed Let’s Encrypt in ISPmanager, you can get yourself a self-updated SSL-certificate for the domain.
Be sure to develop a user with the configured web-domain and valid domain name open to world-wide DNS.
If you have the UFW firewall enabled, as recommended by the prerequisite guides, you’ll need to adjust the settings to permit HTTPS traffic.
Upon installation, Apache registers several different UFW application profiles.

It is possible to leverage the Apache Full profile to permit both HTTP and HTTPS traffic on your server.
To automatically obtain and configure SSL for your web server, Certbot must find the appropriate virtual host within your Apache configuration files.