Facebook Explains What Happened in Massive Blackout: 'We're Working to Understand More' The mass outages affected millions of users worldwide.

Blame it on Mercury Retrograde or the beginning of spooky season, but social media users worldwide were in for quite a scare on Monday when Facebook went completely dark due to internal technical outages.

These blackouts also included Facebook-owned Instagram and international messenger app WhatsApp.

Santosh Janardhan, VP of Engineering and Infrastructure at Facebook, penned a statement on the company's website late Monday night apologizing to users and offering an explanation for the widespread outages.

Related: Facebook CEO Mark Zuckerberg's Net Worth Dropped by $7 Billion in One Day

"We are sorry for the inconvenience caused by today's outage across our platforms," he began. "The underlying cause of this outage also impacted many of the internal tools and systems we use in our day-to-day operations, complicating our attempts to quickly diagnose and resolve the problem.

Janardhan said that Facebook wants to "make clear" that the core cause of the blackouts was due to a "faulty configuration change" on "backbone routers."

"This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt," he said.

The outages left millions refreshing and constantly checking their apps and pages to see if services had been restored.

Facebook's stock continued its recent downward trend by dropping nearly 5% on Monday, with CEO Mark Zuckerberg losing an estimated $6 billion off of his net worth in the hours following the crash.

As of Tuesday morning, Zuckerberg's estimated net worth was $117.4 billion.

Julian Dunn, director of product marketing at PagerDuty, weighed in on the effects of the outages on company revenue and financials.

"Outages like Facebook and Instagram mean big money for companies. Some companies are estimated to lose nearly five million dollars for every hour of the outage to their website," he said. "Although multi-hour outages are relatively rare, even short ones -- 15 minutes or half an hour -- have an outsized impact, as impatient consumers are all too eager to leave a down site and go elsewhere."

Facebook currently has around 2.89 billion monthly active users, while Instagram has an estimated 1 billion.

"We understand the impact outages like these have on people's lives, and our responsibility to keep people informed about disruptions to our services," Janardhan said in his letter. "We apologize to all those affected, and we're working to understand more about what happened today so we can continue to make our infrastructure more resilient."

As of 10 a.m. Tuesday morning, Facebook was up 1.17% from the same time the day prior.