How to fix a failed send
What to do when a campaign, workflow, test, or transactional send is rejected.
You got a send failure such as Message rejected, Email delivery failed, Workflow email send failed, or campaign send failed. The message never left, or the provider refused it.
What to change
- Open the linked campaign, workflow, or Domains page from the notification.
- Read the last sentence of the alert — it names the provider code.
- Fix the matching cause:
| Code / wording | Fix |
|---|---|
MAIL FROM / MailFromDomainNotVerifiedException | How to fix MAIL FROM |
| Domain not verified / identity paused | How to verify a sending domain |
| Invalid from/to/subject/headers | How to fix an invalid email parameter |
| Configuration set missing / sending paused | How to fix sending infrastructure |
| Rate or daily quota | How to fix sending rate or daily quota |
| Internal error / “bug on our side” | Nothing on your DNS. Email [email protected] with the org slug and the technical detail. |
| Message rejected (generic) | Confirm the From address uses a verified custom domain, the recipient is not suppressed, and the campaign still renders. Then retry. |
- After DNS changes, verify the domain, then resend or resume the campaign/workflow.
Fallback already delivered through another domain? See How to fix a fallback-domain send.