New Delhi: Facebook, Instagram and WhatsApp services started coming online on Tuesday morning Indian time, after nearly six hours into an outage that paralyzed the social media platform.
The platforms were hit by outages late on Monday evening after millions of users across the world were unable to use the apps as well as the websites.
"To the huge community of people and businesses around the world who depend on us: we're sorry. We've been working hard to restore access to our apps and services and are happy to report they are coming back online now. Thank you for bearing with us," Facebook said in a tweet, minutes before the services were up online.
Meanwhile, Downdetector, a site that monitors reports of outages across the internet, said the Facebook service outage is the largest it has ever seen.
"The Facebook outage continues and has become the largest outage we've ever seen on Downdetector with over 10.6 million problem reports from all over the globe," the company said in a post on Monday
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, fell 4.9% on Monday, their biggest daily drop since last November, 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.
Soon after the outage started, Facebook acknowledged users were having trouble accessing its apps but did not provide any specifics about the nature of the problem or say how many users were affected by the outage.
Several Facebook employees who declined to be named said that they believed that the outage was caused by an internal routing mistake to an internet domain that was compounded by the failures of internal communication tools and other resources that depend on that same domain in order to work.
Facebook, which is the second-largest digital advertising platform in the world, was losing about $545,000 in U.S. ad revenue per hour during the outage, according to estimates from ad measurement firm Standard Media Index.