5.1.9 Domain Is Not Configured to Send Emails

Resolving the 5.1.9 SMTP error when sending emails.

This guide explains the 5.1.9 Domain <domain> is not configured to send emails error that occurs when using ImprovMX SMTP.

What Causes This Error

The error happens when attempting to send via ImprovMX SMTP (available on Premium and Business tiers), but the system cannot apply the required DKIM signature to outgoing messages. This occurs because DKIM / DMARC records are not resolving during the time of sending.

ImprovMX SMTP requires active DMARC/DKIM authentication on your domain to properly sign emails as the authenticated sender. Without these records, emails fail to send and appear in your dashboard logs with an error status.

How to Resolve

  1. Access your domain's DNS Settings tab in the Dashboard
  2. Navigate to the DKIM and DMARC records section (visible once you've created at least one SMTP credential)
  3. Create the required DNS records:
    • DKIM records (CNAME type)
    • DMARC records (TXT type)
  4. Add these records through your domain's DNS control panel
  5. Allow propagation time (typically a few hours, occasionally 24-48 hours)

Once propagation completes, you can send emails from your SMTP alias successfully.

Additional Resources

See our in-depth guide on adding DKIM and DMARC records to your domain for complete implementation details.

Still have questions? Feel free to reach out to our support team!