Ipv6 Network unreachable Debian

Been trying to configure ipv6 on my proxmox server for about an hour now and I just can't seem to get it right.

/etc/network/interfaces:

auto lo
iface lo inet loopback

auto vmbr0
iface vmbr0 inet static
    address xxx.xxx.xxx.2
    netmask 255.255.255.0
    gateway xxx.xxx.xxx.1
    bridge_ports eth2
    bridge_stp off
    bridge_fd 0

iface vmbr0 inet6 static
    address 2604:xxxx:xxxx:xxxx:0000:0000:0000:0003
    netmask 128
    gateway 2604:xxxx:xxxx:xxxx:0000:0000:0000:0001

ip -6 route

2604:xxxx:x:x::3 dev vmbr0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
fe80::1 dev venet0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
fe80::/64 dev venet0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
fe80::/64 dev eth2  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
fe80::/64 dev vmbr0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0

ip -6 route add 2604:xxx:x:x::3/128 via 2604:xxx:x:x::1

RTNETLINK answers: No route to host

ping6 google.com

connect: Network is unreachable

Would appreciate any help that could be provided. It is probably something pretty simple but I am a bit new to debian.