Kustomer experienced a minor incident on May 26, 2026 affecting Channel - Chat and Channel - Chat, lasting 2h 7m. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- monitoring May 26, 2026, 10:14 PM UTC
Kustomer has implemented an update to address an event affecting WhatsApp that caused messaging failures. Our team is currently monitoring this update to ensure the issue is fully resolved. Please expect further updates within the next 30 minutes, and reach out to Kustomer support at [email protected] if you have additional questions or concerns.
- resolved May 27, 2026, 12:21 AM UTC
This incident has been resolved. Our teams have confirmed recovery and platform stability following mitigation efforts. We will be reaching out independently to affected orgs to provide additional context and follow-up as needed. Thank you for your patience while we worked through this issue.
- postmortem Jun 11, 2026, 09:19 PM UTC
## Summary On May 26, 2026, some customers experienced failures when sending WhatsApp messages from existing conversations. The issue affected outbound message delivery for a subset of WhatsApp configurations. Service was restored after the responsible change was rolled back, and the issue is now resolved. ## Impact During the incident window, outbound WhatsApp messages failed for some existing conversations. Newly created conversations were less consistently affected, and impact varied by account configuration. Customers may have seen message-send failures or provider errors while attempting to send WhatsApp messages. ## Timeline All times EDT. * **4:05 PM:** The incident window is believed to have begun after a recent WhatsApp-related change. * **5:54 PM:** Active investigation began. * **5:56 PM:** The team identified a likely connection to recent WhatsApp sender-selection behavior and started a rollback. * **6:05 PM:** Rollback completed. * **6:17 PM – 7:47 PM:** The team validated recovery across affected examples and narrowed the underlying cause. * **8:21 PM:** The incident was declared resolved. ## Root cause The incident was caused by an issue in WhatsApp phone-number lookup and sender selection. A recent change expanded support for multiple valid phone-number formats in certain countries. In some cases, that allowed the system to resolve the wrong sender configuration for an existing conversation. When that happened, outbound sends could target an invalid or unavailable sender identity, causing WhatsApp message delivery to fail. ## Resolution We mitigated the incident by rolling back the relevant WhatsApp change. After the rollback, we verified recovery against affected examples and confirmed that the incident was resolved. ## Preventative actions * Move WhatsApp sender resolution toward more stable identifier-based matching rather than relying on ambiguous phone-number formatting. * Expand regression coverage for country-specific phone-number formatting edge cases. * Improve monitoring and alerting for message delivery failures and queue growth. * Improve testing workflows for WhatsApp changes before production rollout.