Since I moved my server to ipv6 only federation broke. I'm guessing this server is acessible trough the cloudflare proxy, but the underlying server is unable to connect to mine
This surprises me since Cloudflare has AAAA records listed for lemmy.world. Do you know your way around tcpdump? If so, it might be interesting to see what's happening with traffic to those addresses. My desktop doesn't have v6 right now (sigh) or I'd be testing that myself ...