Nginx Web Ui doesn't work

Hello,

I installed the nginx-plugin but I’m not able to open the Web UI.

I tested the three ipv6-addresses of my hassio (with and without https):
https://[2x02:xxx:233:7f20::xxxx]:81/
https://[fx80::xxx:3644:c9cc:xxxx]:81/
https://[2x02:xxx:233:7f20:5e06:733:xxxx:a837]:81/

Is there any issue with ipv6?

Thank you for help!