Facebook on Tuesday cited faulty configuration changes on its routers as the root cause of the nearly six-hour outage that prevented the company’s 3.5 billion users from accessing its social media and messaging services.
At the same time, the business website Fortune reported that it had cost Facebook founder Mark Zuckerberg an estimated $6 billion at one point as shares plummeted.
Zuckerberg has already apologised to those affected by the outage.
“Our engineering teams have learned that configuration changes on the backbone routers that coordinate network traffic between our data centers caused issues that interrupted this communication,” he also said.
The services were down from about 16:00 GMT until around 22:00 on Monday.
But the company said there was “no evidence that user data was compromised”.
The outage was the second blow to the social media giant in as many days after a whistleblower on Sunday accused the company of repeatedly prioritizing profit over clamping down on hate speech and misinformation.
Shares of Facebook, which has nearly 2 billion daily active users, opened lower after the whistleblower report and slipped further to trade down 5.3% in afternoon trading on Monday.
They were on track for their worst day in nearly a year, amid a broader selloff in technology stocks.