Billions of users have become stranded as Facebook and WhatsApp sites crahed.
Facebook, Instagram, WhatsApp and Facebook Messenger all went down on Monday afternoon with users worldwide reporting the crashes.
Other products that are part of the same family of apps, such as Facebook Workplace, also stopped working.
The online services all share an infrastructure and are owned by Facebook, which is owned by American billionaire Mark Zuckerberg.
The crash started around 16:41BST, according to the website Downdetector. While just two problems were reported at 16:26, the site says, this had jumped to more than 27,000 just fifteen minutes later.
According to The National, users attempting to access Facebook on their browser have been shown a blank error page, while those using WhatsApp or Instagram mobile apps have been able to view existing content, but nothing new has loaded.
“We’re aware that some people are having trouble accessing Facebook app. We’re working to get things back to normal as quickly as possible, and we apologize for any inconvenience,” Facebook said via @facebookapp
Posting on Twitter, which has not seen any issues, the Facebook app said it was aware of outages affecting “some people”.
The firm said: “We’re aware that some people are having trouble accessing Facebook app. We’re working to get things back to normal as quickly as possible, and we apologize for any inconvenience.”
WhatsApp also used Twitter to say that they were working on solving issues affecting their services.
The app tweeted, “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!”