Make minecraft server accessible via ipv6 address?

Question above, I have released all ports, but unfortunately you can still not access the server from another network.

I have a Fritz box via ds lite tunnel. I know it should work, but how?

Maybe one of these links will help you:

http://www.portmapper.de/

https://www.arvid-bauer.de/data/frtizbox-6490-auf-ipv4-umstellen-lassen/

Otherwise you can also rent a free https://aternos.org/...s.org/:de/ server.