Sending DHCPv6 vendor options via dhcpd (isc-dhcp-server) and receiving via systemd-networkd DHCPv6 client

I am trying to send DHCPv6 vendor options via Dhcpd
in dhcpd6.conf

option space FOO;
option FOO.url code 1 = text;
subnet6 <IPV6>::/64 {
    range6 <START_RANGE>::2 <END_RANGE>::6;
    option dhcp6.name-servers 2001:4860:4860::8888, 2001:4860:4860::8844;
    option dhcp6.domain-search "example.com";
    vendor-option-space FOO;
    option FOO.url "HELLO";
}

In systemd-networkd config (/etc/systemd/network/ ) file , I have :

[DHCPv6]
WithoutRA=solicit
VendorClassIdentifier="Mist Edge"
RequestOptions=17

I am not receving any vendor options. Am I missing something in server or client side ? I want to send a text string from DHCPV6 server to to DHCPv6 client (networkd)

Appreciate any inputs