Billions of users couldn’t access Facebook, WhatsApp, Messenger, and Instagram, for several hours on October 4. The mass outage led Facebook to issue an apology. Later on that day, Santosh Janardhan, vice president of Infrastructure at Facebook, wrote in a blog post, “To all the people and businesses around the world who depend on us, we are sorry for the inconvenience caused by today’s outage across our platforms.”

Users were unable to send messages and refresh their feeds due to the outage. Janardhan stated that the outage occurred as a result of “configuration changes on the backbone routers” but didn’t delve into further details about these changes. 

The “issues” caused by these changes disturbed the flow of traffic between routers in Facebook’s data centers across the globe, said Janardhan. WhatsApp, Instagram, and Facebook stopped functioning shortly before noontime ET. Server errors were displayed on the websites and apps for Facebook’s services.

Approximately six hours after the outage, just after 7 pm ET, Mark Zuckerberg, Facebook CEO, announced on his Facebook page: “Facebook, Instagram, WhatsApp, and Messenger are coming back online now. Sorry for the disruption today – I know how much you rely on our services to stay connected with the people you care about.”

Since 2008, Facebook hadn’t had an outage that stretched for that long a duration. In 2008, approximately 80 million users were affected because a bug led the site to go offline for nearly a day. Currently, 3 billion users are on Facebook.

A similar outage occurred in 2019 but lasted for only an hour. The reason behind that incident was a server configuration. However, the latest outage took place one day after the whistleblower behind the leak of private internal research to both Congress and The Wall Street Journal revealed herself before appearing on CBS’ “60 Minutes” for an interview. 

The documents not only revealed that the company was aware of how Instagram was negatively affecting younger users but also how Facebook’s algorithm propelled misinformation.