We have activated dedicated IPv6 addresses for all web hosting accounts yesterday. For you as the operator of the accounts, there is no need for further action.
If you are interested in the differences of IPv4 and IPv6 protocol, this will help you: https://www.heise.de/tipps-tricks/IPv4-und-IPv6-Was-sind-die-Unterschiede-6114077.html
Update
If there is a reason that you do not want to use IPv6 on your website at this time, follow these steps.
- Open web hosting management
- Find and open the "Zone Editor" menu item
- Click Manage on the far right of your domain.
- Delete all entries of the type "AAAA".
Finally, be patient. Due to DNS, it may take a few hours for the change to be detected by visitors to the website and reconnected to the old V4 standard.
Optimally, however, you fix the cause of the deactivation. Sooner or later you will have to deal with it.