2021 Facebook outage

On October 4, 2021, at 15:39 UTC, the social network Facebook and its subsidiaries, Messenger, Instagram, WhatsApp, Mapillary, and Oculus, became globally unavailable for a period of six to seven hours.

[9] The outage was caused by the loss of IP routes to the Facebook Domain Name System (DNS) servers, which were all self-hosted at the time.

[15] Facebook gradually returned after a team got access to server computers at the Santa Clara, California, data center and reset them.

[16] The outage cut off Facebook's internal communications, preventing employees from sending or receiving external emails, accessing the corporate directory, and authenticating to some Google Docs and Zoom services.

[24] The outage had a major impact on people in the developing world, who depend on Facebook's "Free Basics" program, affecting communication, business and humanitarian work.

"[26] Alexandria Ocasio-Cortez, a U.S. representative from New York, tweeted about the outage, asking people to share "evidence-based" stories on Twitter, making fun of Facebook's reputation for spreading factually questionable content.