Outlook email outage affects users around the world — Microsoft 365 global outage Nov 12-13 disrupted email, Teams and cloud apps for hours.
Timeline:
- 2:45 pm UK time Nov 12, Teams failure in North America first
- 4:17 pm, Exchange Online incident widened, Microsoft status page said users may be unable to connect to mailboxes in Exchange Online through multiple connection methods
- Initially said Americas, later confirmed could affect connectivity for users in any region
- By 1 pm ET 138,058 Outlook reports, 97k+ Outlook, 38k Microsoft 365, 4.5k Teams at 2:07 pm ET per Downdetector, map showed 74 countries across Americas, Europe, Asia, Africa
- In India peak around 1:30 am IST Nov 13, about 1.3 lakh reports, fell to ∼34,490 by 4:30 am IST
- Singapore 250 reports at 7:05 am, doubled to 535 by 7:55 am local
Cause per Microsoft: Not traffic surge. Elevated load driven by large number of servers being unexpectedly unavailable after failing automated health checks, shifting load onto remaining infrastructure. Core process on affected servers becoming overwhelmed, causing them to stop responding.
Services impacted: Exchange Online, Microsoft Teams, SharePoint Online, Microsoft 365 Copilot, OneDrive, Word, Excel, PowerPoint, Defender XDR, Purview services. Third-party AI also: OpenAI reported new connections through Microsoft connectors might be broken, Anthropic reported upstream provider issue affecting Microsoft 365 connector.
Fix attempts:
- Paused all deployments
- Redistributing connection traffic across broader worldwide infrastructure to balance load
- Validated alternative health check method on subset, allowed servers to return to service, applying more broadly
- Temporarily limiting which types of traffic can reach affected infrastructure
- Returning portion of affected servers, remain stable so far, but warning servers could become unresponsive again once receiving traffic
Governments affected: State of Michigan reported technical issues with email and Microsoft apps due to widescale outage. Workhorse Group electric truck maker delayed quarterly results.
As of 2:10 pm ET some services started to recover, Teams restored in North America per AP, but Outlook remained degraded. By 10:58 pm UK Nov 12 Microsoft had not declared incident resolved, tracking as EX1550543 and MO1550821 in admin centre. Emails sent during outage may arrive late.
Microsoft said aggressively pursuing all pathways to reduce impact, seeing positive results to restart infrastructure, but root cause still not disclosed.
Tags: #OutlookOutage #Microsoft365 #ExchangeOnline #TeamsDown #Downdetector