Facebook and its WhatsApp and Instagram apps went dark at around noon Eastern time, triggering a record 10.6 million problem reports, according to website monitoring group Downdetector.
It said the outage was the largest such failure it had ever seen.
Meanwhile checks by Newsclickng.com revealed that the services were restored early Tuesday morning in Nigeria.
Around 5:45 pm ET, some Facebook users began to regain partial access to the social media app.
WhatsApp continued to have connection problems for at least some people.
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.
Security experts said the disruption could be the result of an internal mistake, though sabotage by an insider would be theoretically possible.
“Facebook basically locked its keys in its car,” tweeted Jonathan Zittrain, director of Harvard’s Berkman Klein Center for Internet & Society.
The Independent of London explained what could have gone wrong:
“Facebook’s problems appeared to be related to the domain name system, or DNS. That is often referred to as the phone book of the internet, taking the URL a person types into their browser – such as Facebook.com – and turning it into a numerical address that can then be asked for the data that makes up the website being accessed.
“The company runs its own DNS, unlike many other smaller firms. As such, it is at liberty to make changes itself – and to remove those records, too, which was what seemed to have happened at some point on Monday.
“Without the correct DNS configurations, browsers were unable to access the Facebook website, and apps could not properly call the servers needed to fill up Instagram with new posts or WhatsApp with new messages.
“In all, a vast array of Facebook of services went down. They included not just its large apps but virtual reality platform Oculus, and office social network Workplace”.
Today’s outage is also not the worst or the longest in the company’s history.
In 2019, that record was set by a technical issue that lasted for more than 24 hours, and about which Facebook was largely cryptic in its explanations.
