Hetzner with IPv6 /64

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Hi everyone,
I'm currently trying to setup a new host on a Hetzner dedicated server. The server is running Hyper-V with a pfsense as VM. The LAN-Side of the pfsense is a private switch in hyper-v to 2 windows server. The goal would be, that the pfsense is reachable using ipv6 and the 2 servers as well.

I already setup the wan side of the pfsense. I got a /64 and a /56 from Hetzner. I set the 2a01:XXXX:XXXX:2d4f::2/64 for the WAN using the fe80::1 gateway. This works as intended and the pfsense can communicate using IPv6. For the LAN I wanted to use: 2a01:XXXX:172:f400::2/56. But this doesn't work. I can't ping google trough pfsense nor do the servers.

What have I done wrong or how would I configure this correctly to make this work?

Thanks for your help in advance!
Lars