Configure ipv6 on OVH KS independent server

admin

Someone has configured it before.
Manual configuration is incorrect, what's the problem?

vmbr0 auto
iface vmbr0 inet static
  address 158.69.xx.75/24
  gateway 158.69.xx.254
  bridge-ports eno1
  bridge-stp off
  bridge-fd 0
  hwaddress 0C:C4:7A:47

9:14

iface vmbr1 inet6 static
        address 2607:5300:120:a4b::1
        netmask 64
        post-up /sbin/ip -f inet6 route add xx:5300:0120:0aff:00ff:00ff:00ff:00ff dev vmbr0
        post-up /sbin/ip -f inet6 route add default via xx:5300:0120:0aff:00ff:00ff:00ff:00ff
        pre-down /sbin/ip -f inet6 route del default via xx:5300:0120:0aff:00ff:00ff:00ff:00ff
        pre-down /sbin/ip -f inet6 route del xx:5300:0120:0aff:00ff:00ff:00ff:00ff