EC2 with Ubuntu 16.04 in IPv6 VPC unreachable from outside

Hi All,

I am struggling from couple of days to ssh my IPv6 enabled ec2 instance in Ubuntu 16.04.3 LTS using ipv6 address, it is throwing Network error. But when I tried to ssh the same instance using elastic IP address I am able to connect.

Here are my route info:

ubuntu@ip-172-30-3-113:/$ ip route show default via 172.30.3.1 dev ens5 172.30.3.0/24 dev ens5 proto kernel scope link src 172.30.3.113

ubuntu@ip-172-30-3-113:/$ ip -6 route show 2600:1f18:3bb7:6400:xxxx:xxxx:xxxx:c64b dev ens5 proto kernel metric 256 pref medium 2600:1f18:3bb7:6400::/64 dev ens5 proto kernel metric 256 pref medium fe80::/64 dev ens5 proto kernel metric 256 pref medium default via fe80::808:5aff:fe08:c396 dev ens5 proto ra metric 1024 expires 1799sec hoplimit 255 pref medium

**Security Group: ** Allow All IPv6 and IPv4 with ssh (22) permission

Route Table: Both Ipv6 and Ipv4 pointing to same Internet Gateway

Network ACL: Allow all traffic inbound and outbound

Not sure what I am missing here - to connect the ec2 instance via ssh. Could you please give me some leads what I might be missing in the configuration.

Regards, Rintu