MessageBird - unable to send outbound replies PROD 1

Incident Report for Kustomer

Postmortem

Summary

On June 25, 2026, some customers were unable to send outbound WhatsApp replies from within Kustomer. The issue affected reply sending for a subset of WhatsApp channel configurations, which disrupted agent workflows and prevented some automated outbound messages from being sent through the same path.

The issue was identified and resolved the same day. Service was fully restored, and the platform is operating normally.

Root cause

A change released earlier that day introduced stricter validation in the outbound WhatsApp reply flow. For a subset of supported channel configurations, valid sender values were incorrectly rejected before messages were sent. This caused reply attempts in those configurations to fail.

The issue was limited to specific WhatsApp channel setups and did not affect all WhatsApp traffic equally.

Timeline

June 25, 2026, approximately 22:12 UTC — Reports began coming in that outbound WhatsApp replies were failing for some customers.
Shortly after detection — Investigation confirmed the issue was tied to a recently released validation change in the outbound reply flow.
June 26, 2026, approximately 01:07 UTC — A fix was deployed and reply sending was restored.

Lessons and improvements

Validation changes for messaging flows now require broader test coverage across supported channel configuration variants before release.
Additional safeguards are being added to reduce the risk of valid outbound requests being rejected.
Monitoring and regression checks around outbound messaging paths are being strengthened to detect similar issues more quickly.

Posted Aug 06, 2026 - 10:13 EDT

Resolved

Kustomer has resolved the issue affecting PROD 1 that impacted the ability to send outbound messages through MessageBird.

Our team has verified that the fix has been successfully deployed and service has been restored. If you continue to experience issues sending outbound MessageBird messages, please contact Kustomer Support at support@kustomer.com

We apologize for the disruption and appreciate your patience while we worked to resolve the issue.

Posted Jun 25, 2026 - 19:30 EDT

Monitoring

Kustomer has identified and implemented a fix for the issue affecting PROD 1 that impacted the ability to send outbound messages through MessageBird.

Our team is actively monitoring the platform to ensure the fix remains effective and that service has fully recovered. If you continue to experience issues sending outbound MessageBird messages, please contact Kustomer Support at support@kustomer.com.

We will provide another update once monitoring is complete or if there are any significant developments.

Thank you for your patience.

Posted Jun 25, 2026 - 19:06 EDT

Update

Posted Jun 25, 2026 - 19:05 EDT

Identified

Kustomer has identified the cause affecting PROD 1 that is impacting the ability to send outbound messages through MessageBird.

Please expect another update within the next 30 minutes, as we reach a resolution. If you have any additional questions or concerns, please reply to this conversation or contact Kustomer Support at support@kustomer.com.

Thank you for your patience while we work to resolve this issue.

Posted Jun 25, 2026 - 18:49 EDT

Investigating

Kustomer is aware of an event affecting PROD 1 that may affect the ability to send outbound messages for MessageBird.

Our team is currently working to identify the cause of this issue in an effort to implement a resolution. Please expect additional updates within the next 30 minutes, please reach out to Kustomer Support at support@kustomer.com for any further questions or updates.

Posted Jun 25, 2026 - 18:24 EDT

This incident affected: Prod1 (US) (Channel - Chat).