I have an app whose public IPV6 address is unreachable. It’s a caddy app so at first, I thought caddy was not binding to all interfaces but after consulting with the caddy community the issue doesn’t seem to be on that side because caddy binds to both IPV6 and IPV4 by default.
I’m wondering whether the issue is that the app has been assigned with the wrong address.
I looked at the IP from the Caddy discussion and it seems like it’s working correctly? At least, I can ping that IPv6, so it’s routing right.
@rugwiro does your ISP support IPv6? Mine doesn’t 
I need to use a 6to4 tunnel to test this locally.
You can test this with various tools online. I found IPv6 test - web site reachability and used your app’s hostname in there and it resolved to the right IPv6 and returned an HTTP response (as far as I can tell).
Must be my ISP. It passed the simple test you linked to directly but upon further exploration it appears my ISP doesn’t support IPv6. Thanks for the trouble. IPv6 traffic is still very low in these parts anyway.