HE.net tunnel working on Vultr Ubuntu up/down routes not working

gistfile1.txt

root@vultryyz:~# cat /etc/network/interfaces
# ifupdown has been replaced by netplan(5) on this system.  See
# /etc/netplan for current configuration.
# To re-enable ifupdown on this system, you can run:
#    sudo apt install ifupdown
#
#
# The loopback network interface
auto lo
iface lo inet loopback

auto ens3
iface ens3 inet dhcp
iface ens3 inet6 static
        address 2001:19fo:b001:fb5:5400:02ff:fe0a:1ee8
        netmask 64
        #post-up /sbin/ip -6 route del default dev ens3
        post-up /sbin/ip -6 route del ::/0 default dev ens3
        post-up /sbin/ip -6 route add 2001:19f0:ffff::1/128 via fe80::fc00:2ff:fe0a:1ee8 dev ens3
        pre-down /sbin/ip -6 route del 2001:19f0:ffff::1/128 via fe80::fc00:2ff:fe0a:1ee8 dev ens3



auto he-ipv6
iface he-ipv6 inet6 v4tunnel
        address 2001:470:1c:1da::2
        netmask 64
        endpoint 216.66.38.58
        local 155.138.132.27
        ttl 255
        gateway 2001:470:1c:1da::1