It stopped working in many parts around the world, preventing users from sending messages or posting anything on Instagram.
Downdetector showed there were more than 20,000 incidents of people reporting issues with Facebook services.
Meanwhile, the social media giant's instant messaging platform WhatsApp was unavailable to over 14,000 users, while Messenger was unavailable to nearly 3,000.
Downdetector only monitors outages by compiling status reports from various sources, including user-submitted errors on its platform. The outage could affect a larger number of people.
Hopefully, services will resume soon.
