INC-005: Moved a domain's DNS, and the business email quietly stopped

The website records came across but MX, SPF and DKIM didn't. I traced it record by record until every mail check passed.

severity: SEV-2 | kind: outage | date: 2026-06 | status: RESOLVED

Impact

After moving an Australian client's nameservers to a new DNS provider, their business mailboxes (including the one used for customer quotes) stopped receiving mail.

Summary

The website records came across but MX, SPF and DKIM didn't. I traced it record by record until every mail check passed.

Timeline

• Nameservers switched from the old host to the new DNS provider
• Mail issues reported; the old host's domain health check showed MX, SPF and DKIM warnings
• Compared zones: the new DNS zone had no MX records at all
• Identified the required MX hosts/priorities and SPF/DKIM values
• Restored the records
• All four checks green (MX, SPF, DKIM, DMARC); tested send/receive

Root cause

Only web records were recreated in the new DNS zone; mail records were never migrated.

What didn't work

Resolution

• Restore MX, SPF, DKIM
• Verify all mail checks
• Test both directions

Action items

• [x] Export and diff the full DNS zone before any nameserver change

Lesson

_A DNS move isn't 'the website works'. Email is part of the zone too, and it fails silently._

tags: dns, email, mx, spf, dkim