Facebook Revealed Why It Went Down For Hours & It Cost Mark Zuckerberg Billions

After hours of silent Facebook pages, selfie-less Instagram feeds and dead WhatsApp chats, the parent company of the social platforms finally explained what happened late Monday.

"We believe the root cause of this outage was a faulty configuration change," Facebook wrote on its engineering site last night.

"Configuration changes on the backbone routers that coordinate network traffic between our data centers caused issues that interrupted this communication. This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt."

The company added that it has "no evidence that user data was compromised as a result of this downtime."

The outage lasted nearly six hours on Monday and proved to be quite costly for one person.

Facebook CEO Mark Zuckerberg lost approximately $6 billion in net worth amid the outage, according to Forbes, as Facebook's stock price took a nosedive.

Facebook COO Sheryl Sandberg's wealth was also down to $1.9 billion, Forbes reports.

Meanwhile, the outage hit harder in some parts of the world than in others. Several countries have built their internet and phone networks around Facebook and WhatsApp, meaning citizens were more or less kicked off the web during the outage.

Roughly 25 billion WhatsApp messages and 54 million Facebook messages were not sent because of the blackout, according to ABCD Agency, a Berlin-based firm that ran the numbers based on daily usage data.

They also estimate that people got back a combined 3.6 billion minutes that they would've otherwise spent on Instagram.

The social platforms came back online after 6 p.m. ET on Monday, with Facebook posting an apology message on Twitter.

"To the huge community of people and businesses around the world who depend on us: we're sorry," Facebook wrote.

"Sorry for the disruption today," Zuckerberg wrote on his own Facebook page, after tumbling down to a net worth of $117 billion.

"I know how much you rely on our services to stay connected with the people you care about."