DKIM Setup for SendGrid Sending Domains

January 15, 2026 • InboxGreenEmail Team

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DKIM Setup for SendGrid Sending Domains

Setting up DKIM for your SendGrid sending domains can feel like a daunting task, especially if you are not familiar with email authentication. However, getting this right is crucial for improving your inbox placement and maintaining a good domain reputation. If your emails are bouncing or landing in spam folders, it becomes urgent to address DKIM and other authentication issues. Without proper DKIM setup, you risk having your emails flagged as suspicious, which can harm your business and customer relationships.

At a glance

  • This problem affects SaaS founders, marketers, and technical teams managing email sending.
  • This article will guide you through the DKIM setup process for SendGrid.
  • By following these steps, you will enhance your email deliverability and protect your domain reputation.

When this problem shows up in real life

Imagine you are sending out an important marketing campaign, but instead of reaching your audience, your emails are bouncing back or ending up in the spam folder. You check your email logs and see messages like:

  • DKIM: fail in your email headers, indicating that DKIM is not correctly configured.
  • A support ticket from a customer saying they never received your email, and you find it in their spam folder.
  • Gmail warning messages stating "This message may not be from the sender it claims to be," which can discourage recipients from trusting your emails.

These scenarios highlight the importance of DKIM setup. If you do not address these issues, your email campaigns may suffer, leading to lost opportunities and revenue.

Step by step: DKIM setup for SendGrid sending domains

  1. Log in to your SendGrid account.

    Navigate to the settings section of your account.

  2. Access the Sender Authentication page.

    Click on "Sender Authentication" under the "Settings" menu.

  3. Choose your authentication method.

    Select "Authenticate Your Domain." You will have the option to choose your DNS host.

  4. Enter your domain details.

    Input the domain you want to authenticate. For example, if your domain is example.com, enter that.

  5. Generate DKIM records.

    SendGrid will provide you with DKIM records that you need to add to your DNS settings. It will look something like this:

    example._domainkey.example.com. IN TXT "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCB..."
  6. Add the DKIM record to your DNS.

    Log in to your DNS provider (like GoDaddy, Cloudflare, etc.) and add the provided DKIM record as a TXT record.

  7. Verify your DKIM setup.

    Return to SendGrid and click "Verify." This step ensures that your DKIM record is correctly set up. If it fails, double check the DNS entry.

Common mistakes

  • Missing DKIM record in DNS.

    Symptoms: DKIM fails in email headers.

    Cause: The DKIM record was not added to the DNS settings.

    Fix: Ensure you have copied the DKIM record exactly as provided by SendGrid.

  • Incorrect DNS entry format.

    Symptoms: Verification fails with errors.

    Cause: The TXT record might be formatted incorrectly.

    Fix: Make sure there are no extra spaces or missing quotes in your DNS entry.

  • Using the wrong selector.

    Symptoms: DKIM fails in email headers.

    Cause: The selector used in the DKIM record does not match what SendGrid provided.

    Fix: Double-check the selector in your DNS record and ensure it matches the one from SendGrid.

  • Propagation delays.

    Symptoms: DKIM verification fails immediately after setup.

    Cause: DNS changes can take time to propagate.

    Fix: Wait up to 48 hours and then retry the verification.

Troubleshooting when it still fails

If your DKIM setup seems correct but you are still facing issues, here are some things to check:

  • DKIM: fail in headers → likely cause: DNS record not found.

    What to try next: Use a DNS TXT Lookup tool to check if your DKIM record is visible publicly.

  • Authentication-Results header shows "dkim=none" → likely cause: missing or incorrect DKIM record.

    What to try next: Review your DNS settings and ensure the DKIM record is entered correctly.

  • Emails still landing in spam → likely cause: domain reputation issues.

    What to try next: Check your domain reputation using the Blacklist Checker and address any issues.

  • Support tickets about missing emails → likely cause: DKIM misconfiguration.

    What to try next: Analyze the headers of the emails that were not received using the Email Header Analyzer.

Related checks you should run

Once you have set up DKIM, consider checking the following:

  • SPF, DKIM, and DMARC alignment to ensure all authentication methods are working together.
  • DNS TTL settings and propagation delays to avoid issues with changes not taking effect.
  • Domain reputation, including bounces and spam reports, to monitor your sending health.
  • Email list quality and engagement patterns to maintain a good sender score.

FAQ

Why is DKIM still failing on SendGrid after I added the record?

There could be several reasons for this. First, ensure that the DKIM record has propagated properly. It can take up to 48 hours for DNS changes to take effect. Additionally, double check that the record is entered correctly without any formatting errors.

How long do DNS changes take to apply on SendGrid?

DNS changes can take anywhere from a few minutes to 48 hours to propagate fully. If you have just added your DKIM record, give it some time and then verify again.

Can I use more than one DKIM key with SendGrid?

Yes, you can set up multiple DKIM keys if you have different sending domains. Just make sure each domain has its own unique DKIM record in the DNS.

What if my DKIM record is correct but emails are still going to spam?

If your DKIM record is set up correctly, consider looking into other factors such as your domain reputation, email content, and engagement rates. Using tools like the InboxGreen checker can help identify additional issues.

What to do next

Now that you have the DKIM setup for your SendGrid sending domains, take a moment to verify everything is working correctly. Use the InboxGreen checker to confirm your DKIM, SPF, and DMARC records are configured properly. This will give you peace of mind and help ensure your emails land in the inbox, not the spam folder. Don't forget to monitor your email performance regularly and make adjustments as needed.

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