Customer impact

Between May 6, 2026 and 6:43 pm UTC on May 18, 2026, actionable messages sent through the Microsoft Teams connector were not working for a subset of customers. Customers using Action Center actionable notifications in Microsoft Teams could receive the message, but clicking the action button would not complete the task or create the expected event.

The issue affected the Microsoft Teams connector and Action Center actionable notifications globally.

Root cause

Approximately two weeks before this incident, an update was done to the Microsoft Teams integration migrated from an older Microsoft software development kit to a newer one with a different authentication model. The newer model required tenant-specific authentication for the Microsoft Teams bot, but one endpoint used by actionable notifications was still configured with the previous shared authentication approach.

Because a separate endpoint was updated correctly and appeared to work, the misconfiguration in the actionable-notifications endpoint went undetected. Requests from Microsoft Teams actionable messages could not be authenticated at that endpoint, which prevented action submissions from completing. Customers could not complete Action Center tasks directly from Microsoft Teams.

Detection

The issue was identified during functional testing of actionable notifications across supported communication channels. Additional testing confirmed that the issue affected Microsoft Teams across multiple production regions, indicating that it was not isolated to a single environment.

At the time of the incident, automated end-to-end tests did not exist for this workflow. The incident was declared at 10:54 am UTC on May 18, 2026.

Response

On May 18, 2026, at 11:12 am UTC, we published an initial customer-facing status update stating that we were investigating an issue affecting Microsoft Teams connectors. After identifying the authentication mismatch, we developed a fix, validated it in a pre-production environment, and began deploying it to production.

During validation, we determined that the initial fix only partially restored functionality. We reverted the recent SDK-related changes affecting this workflow and redeployed the previous implementation. We continued to provide status updates while deployment progressed across production environments.

Deployment was completed by 6:26 pm UTC on May 18, 2026. After confirming that actionable notifications were functioning correctly across all production environments and monitoring the service for stability, we resolved the incident at 6:43 pm UTC on May 18, 2026.

Follow up

1. Add end-to-end automated testing for the Microsoft Teams actionable notification flow, including sending a notification and submitting an action from Microsoft Teams.
2. Add post-deployment validation for changes that affect the Microsoft Teams connector code path, so authentication and action-submission regressions are caught before broad production rollout.