Scheduling Outage for some Microsoft Office 365 Accounts

We want to share an update on a recent automation issue, including what happened, how it was resolved, and the steps we’ve taken to prevent it from happening again.

Date/Time: April 21, 2026, 1:40 PM – 4:39 PM PDT
Duration: 2 hours 59 minutes

Customer Impact

During this window, customers using Microsoft Office365 were unable to retrieve interviewer availability or schedule interviews. Existing data was not lost, but new scheduling actions failed until service was restored.

Root Cause

An internal encryption key rotation was completed for several services, but a related dependency used by the calendar service was not updated. As a result, the calendar service was unable to read newly issued Microsoft access tokens, causing scheduling requests to fail for Office365-connected accounts.

Resolution

The calendar service was updated to use the correct dependency compatible with the new encryption keys. Once deployed, scheduling functionality was fully restored and verified in production.

Preventative Actions

• Expand automated test coverage to explicitly validate scheduling flows for Microsoft Office365 accounts.
• Improve internal validation and service dependency checks during encryption key rotations.