Secure Domains with Free SSL in Plesk
To secure a domain or subdomain with a free SSL Certificate in Plesk you can use the the built-in LetsEncrypt plugin.
To do this, login to your Plesk panel and navigate to the Extensions tab.
Search in the top right for the plugin SSL it! and install it.
When it is installed, click in the top menu on My Extensions and open SSL it!.
Here you can see a list of all your domains and subdomains and if they are secured with SSL.
Click on the domain or subdomain for which you want to add the SSL certificate
Click at the very bottom on Install a free basic certificate provided by Let's Encrypt
Add a contact mail address and select if you want to secure the www version of the domain as well (recommended)
If the process was successful, enable HSTS for the recommended period
HTTP Strict Transport Security (HSTS) enforces a secure HTTPS connection for a website,
preventing man-in-the-middle attacks. Attackers are then unable to intercept unencrypted data or manipulate content.
It is therefore recommended that you enable this feature.
That’s it. You can now secure your domain or subdomain with a free SSL Certificate and repeat the process for other domains or subdomains as many times as you want.