• Install needed packages
sudo apt-get install software-properties-common
sudo add-apt-repository ppa:certbot/certbot
sudo apt-get update
sudo apt-get install python-certbot-apache
  • add the correct servername to the configs in /etc/apache2/sites-available/000-default.conf
<VirtualHost *:80>
       # The ServerName directive sets the request scheme, hostname and port that
       # the server uses to identify itself. This is used when creating
       # redirection URLs. In the context of virtual hosts, the ServerName
       # specifies what hostname must appear in the request's Host: header to
       # match this virtual host. For the default virtual host (this file) this
       # value is not decisive as it is used as a last resort host regardless.
       # However, you must set it for any further virtual host explicitly.
       ServerName yourdomain.com <--- modify this line at your config
       ServerAdmin you@yourdomain.com
       DocumentRoot /your/root
  • finally request a certificate for your domain
sudo certbot --apache -d yourdomain.com