Your site is available in HTTPS with a certificate issued by Let's Encrypt.
You can replace this page with your own static files, by mounting your own www root directory as a data volume at /var/www/vhosts/files.marcusschoeler.de.
For more detailed information about static sites, check Serving Static Sites section of the documents.
Documents are available at https://github.com/SteveLTN/https-portal.