Troubleshooting DKIM Issues in Postmark

If your DKIM record isn’t verifying or messages are failing DKIM checks, don’t worry — this guide will help you confirm your setup and fix common problems so your emails authenticate correctly.

Step 1: Confirm your DKIM setup in Postmark

You can check whether your domain’s DKIM record is verified directly from your Postmark account.

Go to your Server → Sender Signatures or Domains tab.
Look at the DKIM status next to your domain.
- ✅ Verified = Postmark is signing your messages successfully.
- ⚠️ Unverified = The record hasn’t been detected yet.

Click Verify to recheck your DNS record. If it still fails, continue to Step 2.

Step 2: Check your DKIM record in DNS

Each sending domain needs a TXT record at this exact host name:

pm._domainkey.yourdomain.com

The value should begin with:

v=DKIM1; k=rsa; p=

Then a long string of characters (the public key).

If you’re unsure how to add or check this, see:
👉 Resources for adding DKIM and Return-Path records to DNS for common hosts

Step 3: Verify with a third-party tool

If Postmark shows your DKIM as unverified, it’s helpful to confirm whether the record is visible publicly.

Try these tools:

If the record isn’t showing, your DNS changes may still be propagating — this can take up to 48 hours.

Step 4: Review common DKIM issues

Step 5: Test a live message

To confirm DKIM is working on real mail:

Send a test email from Postmark to a Gmail or Outlook inbox.
Open the message → click View Original (or View Message Source).
Look for:
```
Authentication-Results: ... dkim=pass header.d=yourdomain.com
```
✅ Pass = DKIM is signing correctly.
⚠️ Fail = Check your DNS configuration again.

Still stuck?

If your DKIM record looks correct but won’t verify, please reach out to Postmark Support .
Include:

Your sending domain
A link to a message from your Postmark Activity page
The full email headers showing the DKIM failure

We’ll take a closer look and help you get fully authenticated.