If Outlook stopped loading on Thursday night, you weren’t alone. Starting around 20:00 Harare time (1pm US Eastern), Microsoft 365 began failing for users around the world. Email, Teams, Copilot and a long list of business tools were affected, and the disruption was still going on Friday morning.
What broke
Outlook and Exchange Online took the worst of it. Users couldn’t connect to their mailboxes, send messages or receive them. Teams, Copilot, SharePoint, Defender, Intune, Power BI and other Microsoft 365 services were also hit, according to ABC News Australia’s live coverage. Downdetector logged about 130,000 Outlook problem reports at the peak, Al Jazeera reported. Downdetector’s map showed affected users in the Americas, Europe, Asia and Africa.
Microsoft is tracking the incident as MO1550821 for Microsoft 365 and EX1550543 for Exchange Online. IT admins can follow both in the Microsoft 365 admin centre, and everyone else can watch the Microsoft 365 status page.
Why Microsoft can’t get it back up
Microsoft says this wasn’t caused by a spike in users. A large number of servers became “unexpectedly unavailable,” and the remaining machines then buckled under the extra load. The company traced the failures to a process that sets up secure connections, which became overwhelmed and stopped handling requests.
Getting service back has been the hard part. Microsoft restarted servers and brought some back online, then warned that they “can become unresponsive again once they receive traffic”. It has since limited some kinds of traffic, rebuilt some servers on an earlier software configuration, and begun rolling back a recent network configuration change that matches the timing of the outage. Microsoft says it has seen partial recovery in some regions but admits the fixes “aren’t resulting in sustained recovery.”
Was it a hack?
No, according to Microsoft. The company says there is “no indication” of malicious activity or a cyberattack. Australia’s government, which invoked a priority support agreement with Microsoft during the outage, said the same after a briefing.
The bigger lesson
The outage shows how much depends on a single provider. In New York, emergency management officials told residents to call 311 or 911 because city email might be delayed. In Australia, regional government service centres closed and some court hearings were postponed.
If your business, school or newsroom runs entirely on Microsoft 365, have a fallback ready: a backup messaging channel, offline copies of important contacts, and a plan for reaching customers when email goes down. You can’t prevent the next outage, but you can be ready for it.
This is a developing story. TechBytes Africa will update it as Microsoft releases more information.
