Incident Report – Microsoft SSO Login Disruption

Summary

On April 23, 2026, we experienced an incident affecting customers using “Sign in with Microsoft” authentication. During the incident window, some users were unable to authenticate into the platform using Microsoft SSO and received login-related authentication errors.

Impact

Customers using Microsoft SSO authentication experienced login failures across all production data centres, including UK, EU, and US environments. Other authentication methods, including Google SSO, were not impacted.

Timeline (CEST)

• 10:46 – Initial customer reports received regarding Microsoft SSO login failures.
• 11:00–12:20 – Additional reports confirmed the issue was affecting multiple customers and environments.
• 12:24 – Internal incident declared and status page updated.
• 12:54 – Engineering team identified and resolved the root cause.
• 13:03 – Incident confirmed resolved and status page returned to operational status.

Root Cause

The incident was caused by an expired secret associated with the production Microsoft authentication application configuration used for Microsoft SSO login flows.

Resolution

The expired secret was renewed and the authentication configuration was updated. Following the update, Microsoft SSO login functionality was restored and validated across affected environments.

Preventive Actions

To reduce the likelihood of recurrence, we are implementing the following actions:

• Improved monitoring and alerting for authentication credential expiration.
• Review and automation of secret rotation processes.
• Additional operational checks around third-party authentication dependencies.

We apologize for the disruption and appreciate customers’ patience while the issue was investigated and resolved.