Quoted from: nytimes.com
Facebook and some of its apps, including Instagram and WhatsApp, appeared to go down at the same time on Monday for many users, who turned to Twitter and other social media platforms to lament the outage.
The social network and its apps began displaying error messages before noon Eastern time, users reported. All of the company’s family of apps — Facebook, Instagram, WhatsApp and Facebook Messenger — showed outage reports, according to the site downdetector.com, which monitors web traffic and site activity.
It was unclear what caused the error messages. Outages are not uncommon for apps, but to have so many interconnected apps at the world’s largest social media company go down at the same time is rare. The company has been trying to integrate the underlying technical infrastructure of Facebook, WhatsApp and Instagram for several years.
Two Facebook security team members, who were not authorized to speak publicly, said it was unlikely that a cyberattack caused the issues. That’s because the technology behind the apps was still different enough that one hack was not likely to affect all of them at the same time.