Debian router behind NAT, client in LAN cant ping server endpoint.

[tfk16onr]

Iam currently stuck getting debian server to work with my client (Ubuntu). The tunnel is working succefully from the server but i cant get it to work for my client. 

From my client i can ping to the server but not to the ipv6 endpoint.
I also enabled port forwarding so it is allowed.

This is my client ips: (For some reason i get two global IP:s)

          inet addr:192.168.0.2  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: yyyy:yyyy:28:26d:798f:d356:1d98:3906/64 Scope:Global
          inet6 addr: fe80::7a0f:d0b7:5638:4909/64 Scope:Link
          inet6 addr: yyyy:yyyy:28:26d:4c54:1bc9:133c:2da1/64 Scope:Global


Server:

radvd.conf
interface eth0
{
   AdvSendAdvert on;

   prefix yyyy:yyyy:28:26d::/64
{
AdvOnLink on;
AdvAutonomous on;
};

RDNSS 2a01:e00::0
{
};

};   



source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.0.10
netmask 255.255.255.0
gateway 192.168.0.1

iface eth0 inet6 static
address yyyy:yyyy:28:26d:f66d:04ff:fe06:f27b
netmask 64
gateway yyyy:yyyy:27:26d::2


auto he-ipv6
iface he-ipv6 inet6 v4tunnel
        address yyyy:yyyy:27:26d::2
        netmask 64
        endpoint 216.66.80.90
        local 192.168.0.10
        ttl 255
        gateway yyyy:yyyy:27:26d::1


I tried several combinations and probably been working with this for over 20 hours now  :o