IPv6 is automatically enabled if you configure IPv6 addresses in the Gaia First Time Configuration Wizard.
If you did not do this, manually enable the IPv6 support in Gaia.
In Gaia Portal:
https://<
IP address of Gaia Management Interface>
In Gaia Clish:
set ipv6-state on
save config
reboot
For more information:
See the R80.10 Gaia Administration Guide.