H/T to reader Skip..
Microsoft 365 took a broad hit today (Nov. 12). Outlook was the epicenter, but Teams, Copilot, OneDrive, SharePoint, Office on the web, and even Defender XDR were caught in it.
Peak: roughly 130,000 Outlook reports on Downdetector around 1 p.m. ET, with tens of thousands more on 365 and Teams.
Scope: started in the U.S./Americas, then Microsoft acknowledged all regions were affected.
Not resolved cleanly: by late afternoon they were still at it — "We're opening all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief." That's not a confident postmortem voice.
What Microsoft actually said the cause was: a large number of servers became unexpectedly unavailable, failed automated health checks, and the remaining infrastructure got strained by the load. They explicitly said the elevated load was not a traffic spike. They also said they found no recent changes that correlate with the start of impact — which is corporate for "we don't know why our own servers fell over."
Worth noticing: AWS and Google users were reporting problems at the same time. Amazon insisted its services were "operating normally" and blamed "an unrelated disruption elsewhere on the internet" for inaccurate reports. When three major providers wobble in the same window, the interesting question is what they share — DNS, CDNs, transit providers, upstream dependencies — and that's precisely the layer nobody gives straight answers about. but "coincidence" isn't a technical explanation either.
