IPv6-configuration on RouterOS with FritzBox as internet-router

Hallo friends,

is there anybody who has experience with ipv6-configuration in a network with a FritzBox as the router for internet access?

I want to use public ipv6-adresses on my devices (pc, notebook) in addition to private ipv4-adresses.

I found a website where the configuration on the Mikrotik-router for ipv6-implementation is shown,
but my MikroTik-Router (hap ac²) does not get a prefix-deligation from the FritzBox. The FritzBox is configured as described on
the mentioned website (see the quote below).

Currently RouterOS v7.1.3 is installed and there are no firewall-rules in the input-table which could drop traffic which is send by the FritzBox to the MikroTik-Router.

On the website I found there you can read the necessary steps to activate prefix-deligation to the MikroTik-Router and I configured it as described in this guide.

Following configuration steps are required on the FritzBox:
Internet → Zugangsdaten → IPv6 → Unterstützung für IPv6 aktiv → Immer eine native IPv6-Anbindung nutzen
Heimnetz → Heimnetzübersicht → Netzwerkeinstellungen → IPv6-Adressen → DHCPv6-Server in der FRITZ!Box für das Heimnetz aktivieren → DNS-Server und IPv6-Präfix (IA_PD) zuweisen

Can anybody help?