This archive report was first published on 5 October 2021.
October 4, 2021, marked a chaotic day for Facebook, Instagram, and WhatsApp users as the social media platforms experienced a massive outage that lasted nearly six hours.
The outage began at around noon Eastern time (1600 GMT), with website monitoring group Downdetector reporting it as the largest such failure it had ever seen.
Facebook Chief Technology Officer Mike Schroepfer apologized for the disruption, stating, "To every small and large business, family, and individual who depends on us, I'm sorry." He added that it "may take some time to get to 100%".
Shares of Facebook, which has nearly 2 billion daily active users, fell 4.9% on Monday, their biggest daily drop since last November, amid a broader selloff in technology stocks.
Security experts suggested that the disruption could be the result of an internal mistake, though sabotage by an insider would be theoretically possible.
Facebook acknowledged users were having trouble accessing its apps but did not provide any specifics about the nature of the problem or say how many users were affected by the outage.
The error message on Facebook's webpage suggested an error in the Domain Name System (DNS), which allows web addresses to take users to their destinations.
Several Facebook employees who declined to be named said that they believed that the outage was caused by an internal routing mistake to an internet domain that was compounded by the failures of internal communication tools and other resources that depend on that same domain in order to work.
