The company said users might be unable to access Exchange Online mailboxes through Outlook on the web, Outlook desktop, Exchange ActiveSync, or REST-based connections, and that email delivery might be delayed. It said Teams’ core messaging and online meetings remained largely functional, but Exchange-dependent features such as calendar access and meeting scheduling could fail.

Microsoft also said that direct access to files stored in SharePoint Online remained functional, while features dependent on Exchange Online could be affected. For Microsoft 365 Copilot, users might be unable to load Copilot Chat or receive responses, and Copilot experiences might be unable to access work data such as email, calendars, and files.

The notification also identified potential impacts to Defender for Office 365 Safe Links, which might be unable to verify URLs clicked in Outlook and Teams, and to some Defender XDR portal pages. Other reported impacts included selected Intune device enrolment and compliance scenarios and Purview functions such as data loss prevention, automatic labelling and communication compliance.