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IPv6 Troubleshooting

IPv6 website not loading

If only IPv6 users have trouble, the AAAA record, IPv6 firewall, routing or web server binding may be wrong.

Common causes

Wrong AAAA recordDomain points IPv6 to the wrong server.Check AAAA records.
IPv6 firewallIPv4 is allowed but IPv6 is blocked.Review separate IPv6 rules.
Server not listeningWeb server only binds IPv4.Enable IPv6 listener.
VPN behaviorVPN blocks or leaks IPv6.Compare with and without VPN.

Checklist

  1. Use DNS Lookup to compare A and AAAA records.
  2. Confirm the IPv6 address belongs to the expected server.
  3. Check port 443 on IPv6 if your tools support it.
  4. Review web server listen directives and firewall rules.
  5. Temporarily remove a broken AAAA record if IPv6 is not ready.

Dual-stack sites need both address families to work. If IPv6 is published but broken, some users may fail while IPv4-only users see no problem.

This issue often appears after enabling IPv6 at a DNS provider without finishing server configuration. The site owner sees the website working on an IPv4-only office network, while mobile users or modern ISPs prefer IPv6 and hit the broken path first. Treat IPv6 as a separate production path: DNS, firewall, web server, certificate and monitoring all need to work for both families.

FAQ

Can I run a website on IPv4 only?

Yes, but IPv6 support is increasingly common and useful.

Why do only mobile users fail?

Many mobile networks prefer IPv6, so broken IPv6 may show up there first.

Should I delete AAAA records?

If IPv6 is broken and cannot be fixed quickly, removing AAAA records can be a temporary mitigation.

Related guides

IPv4 vs IPv6Understand dual-stack.DNS LookupCheck A and AAAA.VPN IP Not ChangingCheck IPv6 leaks.