Apart from Facebook, Whatsapp and Instagram also went down on Monday as people were unable to access them.

In his Facebook post, Mark wrote: "Facebook, Instagram, WhatsApp and Messenger are coming back online now. Sorry for the disruption today -- I know how much you rely on our services to stay connected with the people you care about."

The three apps, which are all owned by Facebook, and run on shared infrastructure, all completely stopped working after 9 PM.

Other products of the same family of apps, such as Facebook Workplace, also stopped working.

Whatsapp  CEO Will Cathcart  also informed users that the messaging service is working now.

"We're entirely back up and running now. We know that people were unable to use @WhatsApp to connect with their friends, family, businesses, community groups, and more today -- a humbling reminder of how much people and organizations rely on our app every day," he said.

"We take our mission seriously, and I'm grateful to everyone who worked hard to bring our service back with the reliability you expect from @WhatsApp . We'll learn and grow from this, and continue working to provide you with a simple, secure, and reliable private messaging app," he said.