If your email event shows Status: enqueue_failed, Error: 401, and Message: Failed parsing response, it usually means Bloomreach successfully contacted your email service provider (ESP), but the ESP returned a 401 Unauthorized response that Bloomreach couldn't properly parse.
In most cases, this points to an email integration or sending-domain issue rather than a problem with the email template itself.
What this means
An enqueue_failed event means Bloomreach couldn't enqueue the email for sending. Because the handoff to the ESP failed, the email was not correctly passed to the provider, and a message_id may not be available for that event.
Most common causes
1. Invalid or changed ESP credentials
A 401 A response can occur when the API key or other integration credentials are incorrect, outdated, or recently changed.
2. Wrong, inactive, or deleted sending domain
This issue can occur when the email integration points to a sending domain that is no longer valid in the ESP, has been deleted, was never fully configured, or is the wrong domain for that project. In practice, Bloomreach still tries to hand off the email using the domain configured in the integration, but the ESP can't correctly authorize or recognize that domain, so the request fails with a 401 Failed parsing response.
3. IP allowlist restrictions in Mailgun
If an IP allowlist was recently enabled in Mailgun, requests from IPs not included on that allowlist can be rejected, even when the credentials are valid.
4. Temporary ESP-side incident
In some cases, the integration is configured correctly, and the root cause is a short-lived ESP-side issue that temporarily produces 401 responses.
How to troubleshoot
- Check whether the issue affects only one send or all emails using the same integration. If many sends are affected, the problem is more likely tied to the integration or domain than to a single recipient.
- Review the email integration settings and confirm:
- The correct integration is selected.
- The configured sending domain is correct.
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The API key or credentials haven't been changed or rotated recently.
- Verify that the sending domain still exists and is active in your ESP account.
- If you recently changed Mailgun IP allowlist settings, confirm that all required sending IPs are included, or temporarily remove the allowlist to test whether that is the cause.
- If the issue only happened during a short time window and later sends succeeded, it may have been a temporary ESP-side incident. In that case, retry or resend the affected emails if appropriate.
When to contact Support
Contact Bloomreach Support if you have confirmed that:
- The integration credentials are correct.
- The sending domain is valid and active.
- There were no recent allowlist or authentication changes.
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And the error is still affecting your sends.
When reaching out, include an example campaign, a customer profile, and integration links, along with at least one recent failed timestamp to help speed up the investigation.