MessageBird - unable to send outbound replies PROD 1

Update timeline

1. investigating Jun 25, 2026, 10:24 PM UTC

   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 [email protected] for any further questions or updates.

2. identified Jun 25, 2026, 10:49 PM UTC

   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 [email protected]. Thank you for your patience while we work to resolve this issue.

3. identified Jun 25, 2026, 11:05 PM UTC

   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 [email protected]. We will provide another update once monitoring is complete or if there are any significant developments. Thank you for your patience.

4. monitoring Jun 25, 2026, 11:06 PM UTC

   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 [email protected]. We will provide another update once monitoring is complete or if there are any significant developments. Thank you for your patience.

5. resolved Jun 25, 2026, 11:30 PM UTC

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

6. postmortem Aug 06, 2026, 02:13 PM UTC

   ## **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.