Service appears to be restored for some Facebook and Instagram users after a global outage that disabled the social media platforms, owned by Facebook Inc, for nearly six hours.
Facebook-owned WhatsApp messaging app was still experiencing issues late on Monday.
In a tweet on Monday evening, Facebook confirmed its apps were coming back online and apologised to users for the outage that affected millions of people across the world.
“To the huge community of people and businesses around the world who depend on us: we’re sorry,” Facebook said. “We’ve been working hard to restore access to our apps and services and are happy to report they are coming back online now.”
Outage tracking website Downdetector.com said it had received 10.6 million reports of problems ranging from the United States and Europe to Colombia and Singapore, with trouble first popping up around 15:45 GMT.
Service were not restored until several hours later in what Downdetector described as “the largest outage we’ve ever seen”.
Earlier in the day, Facebook said on Twitter that it was “aware that some people are having trouble accessing our apps and products”.
“We’re working to get things back to normal as quickly as possible, and we apologize for any inconvenience,” the company said, without specifying exactly what had caused the problem.
A similar message confirming the outage also was posted on WhatsApp’s Twitter account.
The outage came as Facebook is facing mounting pressure in the US, after a leaked internal investigation showed the social media giant was aware of how its Instagram app harmed the mental health of teenagers.