app.flotilla.social or flotilla.social? In either case I believe it's a cname, so IPv6 would depend on my hosting providers.
Discussion
I think it was app. that failed for me
Ok, it looks like render.com doesn't have ipv6 support yet, which is unfortunate. I can't migrate everything right now, but you could self-host flotilla pretty easily.
I'm a big IPv6 user, I only have v6 at home