Microsoft is addressing an Exchange Online outage that prevented customers from accessing mailboxes and calendars across multiple connection methods. While engineers say the Exchange outage has been mitigated, Office.com and Microsoft 365 Copilot web sign‑in issues remain under investigation. #ExchangeOnline #MicrosoftCopilot
Keypoints
- The outage affected Outlook on the web, Outlook desktop, Exchange ActiveSync, and other Exchange Online connection protocols.
- Office.com displayed errors and Microsoft 365 Copilot web sign‑in and web clients at office.com/chat and related domains experienced outages.
- Microsoft identified a section of network infrastructure not processing traffic efficiently and is making configuration changes to remediate the impact.
- Microsoft reported Exchange Online was mitigated on March 16 and will provide a Post‑Incident Report; the Copilot web access issue (MO1253428) is still under investigation.
- Similar Exchange Online access incidents occurred in January (IMAP4) and November (classic Outlook client), indicating recurring service availability problems.