Introduction

A nameserver change can take a working site offline fast if the new DNS provider does not already contain the full live zone. The registrar may point traffic to the new nameservers immediately, while the records users actually need never made the move.

Symptoms

  • The domain stops resolving soon after changing nameservers
  • Public DNS tools show different answers from different resolvers
  • The apex domain fails, subdomains fail, or both disappear entirely
  • The old DNS provider still has the correct zone but is no longer authoritative
  • Mail, verification records, or CDN hostnames break along with the website

Common Causes

  • The new DNS provider does not contain the full zone before delegation changed
  • The registrar points to the wrong nameserver hostnames
  • Glue records or custom nameserver settings are incomplete
  • DNSSEC settings no longer match the new authoritative provider
  • Operators assume propagation is the only issue when the new zone is actually missing records

Step-by-Step Fix

  1. Check the registrar and confirm the exact delegated nameservers match the provider that should now host the zone.
  2. Query the authoritative nameservers directly to see whether the new provider actually has the needed A, AAAA, CNAME, MX, and TXT records.
  3. Compare the new live zone against the old provider or recent DNS exports and recreate anything missing.
  4. If DNSSEC is enabled, verify the DS records at the registrar still match the new provider or temporarily disable DNSSEC until aligned.
  5. Confirm any custom nameservers or vanity nameserver glue records are correct if you use them.
  6. Test root domain and critical subdomains separately so you do not miss partial restoration.
  7. If the new provider is wrong and rollback is safer, switch delegation back only after confirming the old zone is still intact.
  8. Re-test from multiple public resolvers and browsers once the authoritative answers are correct.
  9. For future moves, always migrate the full zone first and validate it before changing delegation at the registrar.