Subdomain in Apache2 VirtualHost is being ignored

Hi all,

On lists.example.org I want to run Mailman3. Mailman3 works perfectly in a Docker Container on my Droplet.

So I wrote a VirtualHost like this:

<VirtualHost *:443> 
    
    ServerName lists.example.org
    Include /etc/letsencrypt/options-ssl-apache.conf
    SSLCertificateFile /etc/letsencrypt/live/example.org/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/example.org/privkey.pem
    ServerAdmin donald@trump.org
    Alias /static /opt/mailman/web/static
    Alias /favicon.ico /opt/mailman/web/static/hyperkitty/img/favicon.ico
    ProxyPassMatch ^/static/ !
    ProxyPass / http://172.19.199.3:8000/
    ProxyPassReverse / http://172.19.199.3:8000/
 
    <Directory />
    Allow from all
    Require all granted
    </Directory>
 
    <Directory /opt/mailman/web/static/hyperkitty/img/>
    Allow from all
    Require all granted
    Options FollowSymLinks
    </Directory>
 
    <Directory /opt/mailman/web/static/>
    Options FollowSymLinks
    Allow from all
    Require all granted
    </Directory>

</VirtualHost> 

When I access lists.example.org, nothing is being displayed. But I can perfectly establish a connection to lists.example.org on port 443. Now comes the weird part: example.org displays the mailing list. So somehow the subdomain lists is being ignored.

This seems like a simple problem but I have found so many misleading tutorials…