Get SSL certificate via LetsEncrypt

letsencrypt certonly --webroot -w /var/www/html -d html.citysports.de.staging.ext.dev

Configure Apache vHost

vi /etc/apache2/sites-available/html.citysports.de.staging.ext.dev.conf

a2ensite html.citysports.de.staging.ext.dev.conf

sudo service apache2 restart