Mimecast incident
Degraded service for SAML authentication on US, USB and UK Grids
Mimecast experienced a minor incident on May 19, 2026 affecting United States Grid and United States B Grid and 1 more component, lasting 10h 21m. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- investigating May 19, 2026, 04:38 PM UTC
We are aware that some customers hosted on our US-B grid may be experiencing issues with SAML login attempts to the Administration Console and associated applications. Other authentication methods are functioning normally. We are currently investigating the issue and updates will be posted here as they become available.
- identified May 19, 2026, 04:58 PM UTC
We believe we have identified the issue affecting some customers hosted on our US-B grid who are experiencing failures with SAML login attempts to the Administration Console and associated applications. Our Engineering team is actively investigating the underlying cause and is currently testing a change to validate the suspected configuration issue. We will provide further updates as they become available.
- monitoring May 19, 2026, 05:23 PM UTC
We have taken mitigation steps and believe we have resolved the issue affecting SAML authentication for customers hosted on our US, USB and UK grids. Successful authentication attempts are now being reported, and we are no longer seeing related errors in our monitoring systems. Our Engineering team is closely monitoring the situation to ensure continued stability. Further updates will be posted here as they become available.