Securing the webinterface

So far I couldn't make that working. 

Useful link

Docs: Securing the Webinterface

Activating the Apache modules

a2enmod ssl
systemctl restart apache2

locate the certificate file:

find /etc/apache2/ -type f -exec grep -Hn '^\s*SSLCertificate.*File' {} \;

/etc/apache2/sites-enabled/000-default

RewriteEngine On
# Never forward request for .well-known (important when using Let's Encrypt)
RewriteCond %{REQUEST_URI} !^/.well-known
# Next 2 lines: Force redirection if incoming request is not on 443
RewriteCond %{SERVER_PORT} !^443$
RewriteRule (.*) https://%{HTTP_HOST}$1 [L]
# This section passes the system Apaches connection mode to the
# instance Apache. Make sure mod_headers is enabled, otherwise it
# will be ignored and "Analyze configuration" will issue "WARN".
<IfModule headers_module>
    RequestHeader set X-Forwarded-Proto expr=%{REQUEST_SCHEME}
    RequestHeader set X-Forwarded-SSL expr=%{HTTPS}
</IfModule>