Apache Setup IPv6 only - Vodafone DS Lite

Hi all,

after successfully installing Nextcloud on my Raspberry PI and accessing it locally, I have some issues configuring my Apache2 Webserver to access from externally.

My internet provider is Vodafone and there is only DS-Lite available. So I read that everything must be configured by IPv6. I have registered a public domain via No-IP and entered my IPv6 address. I have also extended the sites-available page:

<VirtualHost [::]:80>
   ServerAdmin xx
   ServerName xx
   ServerAlias xx
   DocumentRoot /var/www/html

<Directory "/var/www/html">
    AllowOverride None
    Require all granted
</Directory>

   ErrorLog ${APACHE_LOG_DIR}/xx.log
   CustomLog ${APACHE_LOG_DIR}/xx.log combined

</VirtualHost>

My Ports.conf looks like this:

Listen [::]:80
Listen [::]:443

<IfModule ssl_module>
        Listen 443
</IfModule>

<IfModule mod_gnutls.c>
        Listen 443
</IfModule>

In the FritzBox config I have openend the ports 80 and 443 for the IPv6 address.

Creating a certificate via certbot also fails with connections refuse, .well-know issue What else needs to be configured for only Ipv6 access?

Thanks in advance!