DKIM Troubleshooting
Troubleshoot DKIM by verifying signing is enabled, DNS selectors resolve, signatures appear on messages, and d= aligns for DMARC.
Checklist
Enable DKIM in the sending platform, publish selector records, send a test to an external mailbox, inspect DKIM-Signature and Authentication-Results, confirm DMARC alignment.
- M365: enable DKIM and verify selector1/selector2
- Google: generate and publish the Google DKIM key
- ESPs: complete domain authentication wizard
How QuickDMARC helps
Use monitoring to catch regressions after ESP changes or key rotations.
Frequently asked questions
No DKIM-Signature header?
Signing is not enabled or a gateway strips it.
DNS looks right but fail?
Propagation delay, wrong selector, or body modification.
Next read?
DKIM failure and Microsoft 365 / Google Workspace DKIM guides.