Customer Action Needed - Migrate to Certificate Based Authentication (CBA)

Update timeline

1. investigating Jul 16, 2026, 07:32 PM UTC

   We are reissuing this incident statement as Microsoft has recently made the change and we have seen many tenants that have not migrated. Below is the original incident language that was sent in February 2026. Cohesity is issuing this advisory to inform our Cloud Protection Service (CPS) customers of an important change regarding authentication for Microsoft 365 workflows. Microsoft is retiring Azure Access Control Service (ACS), effective April 2, 2026. Currently, ACS is utilized for authentication in certain Microsoft 365 workflows, including backups for SharePoint, OneDrive, Teams, and Groups. After April 2, 2026, backups for these protection jobs will fail unless customers migrate to Certificate-Based Authentication (CBA). To ensure uninterrupted service and data protection, we strongly recommend that all customers review the provided Knowledge Base (KB) article and follow the migration instructions. This impacts all regions and all CCS customers. Recommended Action: All recipients of this Field Notice are advised to review the KB article from the additional Resources section for detailed information and recommended preventive actions. KB article: https://support.cohesity.com/s/article/Steps-to-enable-CBA-Migration-for-CPS Microsoft change announcement: https://learn.microsoft.com/en-us/sharepoint/dev/sp-add-ins/retirement-announcement-for-azure-acs

2. resolved Sep 16, 2026, 01:49 PM UTC

   Final reminder to customers to migrate to certificate based authentication for Microsoft O365 workloads. We are closing this incident. Reminder of this KB article for more information: KB article: https://support.cohesity.com/s/article/Steps-to-enable-CBA-Migration-for-CPS Microsoft change announcement: https://learn.microsoft.com/en-us/sharepoint/dev/sp-add-ins/retirement-announcement-for-azure-acs