A default header provides a fallback From Name and From Email for outbound messages sent via a dedicated sending domain. ensuring deliverability and brand consistency without any manual intervention.
When to Use Default Headers
If a campaign's From address does not align with your dedicated sending domain's DKIM/SPF records, the platform will automatically substitute the default header so the message is still authenticated and delivered.
Even if a typo or misconfiguration causes a non-aligned From address, recipients will see your brand's domain in the From field rather than a rejected or unfamiliar address.
Industries with strict email authentication requirements — such as finance and healthcare — should configure default headers to prevent DMARC rejections or quarantine actions that could interrupt critical communications.
Prerequisites
Before configuring default headers, confirm the following are in place.
Default headers can only be set on dedicated sending domains managed within a sub-account. Agency-level domains do not support per-sub-account default header configuration.
You must have completed DNS setup — including CNAME, DKIM, and SPF records — for your custom sending domain (e.g., email.yourbrand.com).
A green checkmark next to your domain under Settings → Email Service → SMTP Service → Dedicated Domain and IP confirms it is validated and ready.
Setting Default Headers (From Name & From Email)
Default headers are configured per dedicated domain within a sub-account. Navigate to the location below to access the setting.
The default header is applied to emails sent through the dedicated domain only when DMARC alignment fails. If the campaign's From address already aligns with your domain, the campaign's original From Name and From Email are used as-is.
How Default Headers Work in Practice
When creating a broadcast or workflow email, you set a campaign-level From Name and From Email.
If the campaign's From Email (e.g., sales@differentdomain.com) does not match your dedicated sending domain (e.g., email.yourbrand.com), DMARC alignment will fail at send time.
At send time, the platform checks DMARC alignment between the campaign's From address and the sending domain's DKIM/SPF records. One of two things happens:
The email is sent with the campaign's original From Name and From Email.
The platform substitutes the default header you configured — the email is sent with your fallback From Name and From Email instead.
- Recipients see a valid From Name and From Email that matches your authenticated sending domain.
- The email remains DMARC-compliant and is less likely to be rejected or flagged as spam.
Example: Finished Default Header Setup
Scenario
| Setting | Value |
|---|---|
| Dedicated Sending Domain | email.yourbrand.com (validated) |
| Default Header — From Name | YourBrand Support |
| Default Header — From Email | support@email.yourbrand.com |
Broadcast / Workflow Email Configured by the User
| Field | Value |
|---|---|
| Campaign From Name | Jane from YourBrand |
| Campaign From Email | jane@anotherdomain.com (does not align with email.yourbrand.com) |
What Recipients See at Send Time
From: Jane from YourBrand <jane@email.yourbrand.com> (or whatever aligned address you selected)
From: YourBrand Support <support@email.yourbrand.com>
How to Confirm It Worked
- Send a test email using a non-aligned From Email (domain mismatch intentional).
- Open the received email and check its From address — it should match your configured default header.
Best Practices & Considerations
Always set up your fallback header before launching major campaigns. If a DNS or DMARC misconfiguration occurs mid-send, the default header kicks in automatically — but only if it's already been saved.
The default From Email can be any address on your sending domain, but ensure that mailbox is actively monitored or aliased correctly (e.g., support@yourbrand.com forwarding to the right team) so customer replies don't go unread.
Send a small internal test using a non-aligned From address to confirm the platform defaults correctly. Check both inbox placement and DMARC status before rolling out to your full audience.
Changes to DNS records (DKIM, SPF, TXT) can take up to 48 hours to fully propagate. If you launch campaigns before propagation completes and no default header is set, messages may be rejected. Default headers protect against this window.
If you manage multiple brands or departments, create separate sub-accounts — each with its own dedicated domain and default headers — for fully isolated sending control and reputation management.
Common Troubleshooting Scenarios
| Issue | Possible Cause | Resolution |
|---|---|---|
| "Set Headers" option is not visible | You're in an agency-level view, or the domain is not validated under a sub-account. | Switch to the correct sub-account. Add and validate a dedicated domain under Settings → Email Service → SMTP Service → Dedicated Domain and IP. |
| Emails still failing to send after fallback | DNS records (DKIM/SPF) are incomplete or incorrectly formatted. | Double-check DNS entries for your sending domain. Use an online DKIM/SPF validator. Allow up to 48 hours for propagation before testing again. |
| Fallback header not applied when expected | The campaign From address aligns with the sending domain (even if unintentional), so no fallback is triggered. | Verify the campaign's From Email is genuinely non-aligned (domain mismatch). Review DMARC reports to confirm alignment failures. |
| Recipients see the wrong From Name or From Email | The campaign or workflow hard-codes a display name that overrides expectations. | Edit the campaign/workflow From Name and From Email. Ensure the fallback header is correctly spelled and contains no stray spaces. |
| SSL certificate not issued for the sending domain | Missing or incorrect CNAME/DNS records for domain validation. | In Settings → Dedicated Domain, click "Edit DNS Info" and follow the instructions exactly. Wait for propagation before retrying verification. |
Frequently Asked Questions
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