When a website is down, DNS is the first layer to rule out. If DNS returns no address or the wrong address, HTTP tests will only show symptoms.

Useful dig commands

dig example.com A
dig example.com AAAA
dig www.example.com CNAME
dig example.com NS

Troubleshooting checklist

  1. Check A and AAAA records.
  2. Check CNAME records for www or app subdomains.
  3. Check NS records if every record type looks missing.
  4. Compare public resolvers.
  5. Move to HTTP, TLS, and server logs only after DNS is correct.

How to interpret the result

If the answer matches the expected value, DNS is probably not the layer causing the current symptom. Continue with HTTP, TLS, mail server, firewall, or application checks. If the answer is missing, stale, or different between resolvers, keep the investigation in DNS until the public answer is correct.

Support note

When opening a ticket with a DNS provider, include the exact name, record type, resolver tested, returned value, and time of the lookup. That is much more useful than saying “DNS is not working.”