Whatever IP addresses your machine is using, Pi-hole has to be made aware of them.
You can achieve that by running
pihole -r
and then chosing Reconfigure.
With regards to your IPv6 address, you should probably avoid using a public address (2000::/3 range). With a public IP, both your IPv6 prefix and the interface identifier are subject to change (the former by your ISP, the latter by IPv6 Privacy Extensions and the likes), and Pi-hole requires a stable address.
Consider to Use IPv6 ULA addresses for Pi-hole.
If that isn't an option, try using your Pi-hole's link-local IPv6 address (fe80::/10 range).