Facebook, Instagram, and WhatsApp are coming back online after several hours of disruption that impacted millions of people worldwide.

While the users of the three social media platforms remained clueless as they repeatedly received error messages for most of the day, the stocks of Silicon Valley firm Facebook dropped by nearly five per cent as a result.

“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, which owns photo sharing app Instagram and messaging platform WhatsApp, said on Twitter.

Mike Schroepfer, chief technology officer of Facebook, said on Twitter: “Sincere apologies to everyone impacted by outages of Facebook powered services right now. We are experiencing networking issues and teams are working as fast as possible to debug and restore as fast as possible.” “Facebook services are coming back online now… (It) may take some time to get to 100 per cent. To every small and large business, family, and individual who depends on us, I’m sorry,” Schroepfer said in another tweet.

“We’re aware that some people are experiencing issues with WhatsApp at the moment. We’re working to get things back to normal and will send an update here as soon as possible. Thanks for your patience!” said the messaging app which had more than two billion active users in the tweet.

“Instagram and friends are having a little bit of a hard time right now, and you may be having issues using them. Bear with us, we’re on it!” the photo sharing app had tweeted.

The outage of the three popular social media platforms comes a day before one of its whistleblowers was all set to testify before a Congressional committee.

“It was highly unusual to have so many apps go dark from the world’s largest social media company at the same time. More than 3.5 billion people use Facebook and its apps to communicate with one another and conduct business,” The New York Times wrote.

According to The Wall Street Journal, the outage also caused widespread disruptions to Facebook’s internal communication tools, including some voice calls and work apps used for calendar appointments and other functions, according to people familiar with the matter.

The company told employees on Monday morning that the cause of the outage was unknown and some staff were using Zoom to remain connected.