How to Fix DNS Problems

DNS problems are almost always a mismatch between where the domain points and where your services actually live. Check the layers in order.

Check Your DNS Records

The order to check

  • Registrar — is the domain registered, unexpired and not locked?
  • Nameservers — do the NS records point at the DNS provider you actually manage?
  • A / CNAME — does the website record point at your current server or platform?
  • MX — is email routed to your real mail provider? A website migration must not remove these.
  • TXT — one SPF record only, plus DKIM and verification records.

Propagation

Resolvers cache answers for the TTL. Lower the TTL to 300 seconds a day before a planned migration, then raise it afterwards. Without that, expect stragglers for up to 48 hours.

Common mistakes

  • Editing records at the registrar while the nameservers point elsewhere.
  • Publishing both an A record and a CNAME for the same hostname.
  • Removing MX records when moving hosts.
  • Two SPF records, which invalidates SPF completely.