MailFixIt

IONOS Mail email configuration guide

IONOS Mail: DKIM record not verifying

IONOS Mail is not producing a verifiable DKIM signature for the message path you tested.

Problem description

A provider setup symptom may look like:

DKIM record not verifying after a provider DNS change.

Check the sending domain

What this usually means

IONOS Mail is not producing a verifiable DKIM signature for the message path you tested.

Fix it

  1. Confirm which system sent the failing message. If it was IONOS Mail, use the DKIM status or instructions for that mailbox product; if a website, newsletter tool, or other provider sent it, publish that sender’s selector instead.
  2. From the sending service, copy the complete DKIM record name, type, and value for the exact custom domain.
  3. Publish it in the authoritative DNS zone without duplicating the domain suffix or changing CNAME/TXT type.
  4. Remove only a conflicting record at the same selector; unrelated selectors can belong to other active senders.
  5. Enable or verify signing in the sending service, then confirm the new message header has the expected d= domain, s= selector, and dkim=pass.

Common mistake

A DKIM record at one selector cannot validate a message signed with another selector. Public DNS may also be correct while signing remains disabled in the provider.

What MailFixIt can check

MailFixIt can find missing, conflicting, or invalid public DKIM evidence. It cannot activate IONOS Mail, create a mailbox, or enable private account features.

Use the related guides for the exact DNS or authentication warning and verify the corrected path with a new test.

Frequently asked questions

What does MailFixIt check for IONOS Mail?

It checks the public DKIM record and visible conflicts. The provider console and a new message or delivery test are still required.

Should I replace every existing DNS record with the provider values?

No. Confirm the exact record type and owner, preserve unrelated legitimate services, and change only the provider-controlled record required for the intended mail route.

Related email diagnostics

Email delivery delayed or rejected after a DNS migrationDiagnose email that stopped arriving after a DNS change. Compare public MX records with the intended provider and avoid false alarms for mail gateways. SPF is not configured for the envelope sender domainDiagnose SPF missing on a bounce or MAIL FROM subdomain. Check the exact envelope domain, add only authorized senders, and verify safely. DKIM public key record is invalid or revokedDiagnose an invalid or revoked DKIM public key record. Check the exact DKIM selector in public DNS before replacing a sender-provided key.

Primary sources: IONOS Mail official setup guidance.