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Why does email health show Throttled?

The Throttled label in email health means your recent delivery data crossed a risk threshold. It is an informational classification. It does not reduce your sending rate, reject messages, or pause sending.

Why the label appears

Email health evaluates three signals over the selected period:
  • Bounce rate: the share of delivery attempts that bounced.
  • Complaint rate: the share of delivered messages that recipients reported as spam.
  • Delivery rate: the share of completed delivery attempts that reached the receiving mail server.
Each signal is classified as Healthy, Watching, or Throttled. The overall label uses the worst classification among those three signals. See Email tracking and metrics for the current thresholds and calculation details.
The word throttled describes deliverability risk only. Bird does not automatically pause email sending when a health signal enters this band.

What to do

Use the signal and its breakdowns to find the source:
  1. Use By domain, By IP, By tag, and By broadcast on the Metrics page to find where the change is concentrated.
  2. Stop or reduce a broadcast that is producing bad signals while you investigate.
  3. Remove invalid addresses and confirm that recipients consented to the mail.
  4. Check domain authentication and recent sending-volume changes.
  5. Resume with engaged recipients and increase volume gradually after the rates recover.
The list hygiene guide covers the cleanup workflow. The warming guide explains how to increase volume safely.

If sends are slow or refused

Treat a delivery problem separately from the health label. Inspect the API error, recipient event, and dashboard notice before changing your integration. Common causes include:
  • an API rate limit with a Retry-After value
  • a recipient on the suppression list
  • an unverified sending domain or onboarding-domain restriction
  • a billing or account restriction
  • a temporary deferral from the receiving mail server
Follow the error's remediation. If the response does not explain the restriction, select Feedback > Contact us and include the request ID.

Next steps