Facebook has apologised for the outage which impacted the social media giant, along with Instagram and WhatsApp, for several hours late on Monday.
In a statement posted to Twitter at 11.31pm, Facebook Engineering confirmed the platforms were coming back online and thanked its millions of users around the world “for bearing with us”.
“To the huge community of people and businesses around the world who depend on us: we’re sorry,” the statement said.
“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.”
The platforms had confirmed on Twitter they were aware of issues and worked to resolve them after thousands of people reported outages shortly before 5pm on Monday.
Users were able to access Facebook and Instagram from late on Monday evening, but many still faced problems on WhatsApp.
Security experts speculated the problem came following network changes, with the cause still unconfirmed.
Adam Leon Smith, of BCS, The Chartered Institute for IT and a software testing expert, said: “The outage is caused by changes made to the Facebook network infrastructure.
“Many of the recent high-profile outages have been caused by similar network level events.
“It is reported by unidentified Facebook sources on Reddit that the network changes have also prevented engineers from remotely connecting to resolve the issues, delaying resolution.
“Notably, many organisations now define their physical infrastructure as code, but most do not apply the same level of testing rigour when they change that code, as they would when changing their core business logic.”
However, cyber security specialist Jake Moore said there is a “chance” the issue could be related to a cyber attack.
He told the PA news agency: “There have been many reports and I’m struggling to find out exactly what has happened- I’m reading it could be DNS related, which means there is an issue with the connection not knowing where to go to your device.
“It could well be a human error or a software bug lurking in the shadows but whatever it is Facebook needs to do its best to mitigate the problem of causing more panic about this.
“The biggest problem is fears over a cyber attack but as we saw from Fastly in the summer I would hedge my bets on that not being the case as we’re talking about one of the biggest companies in the world, but there’s always a chance.”
The New York Times reported the issue likely stemmed from a misconfiguration of Facebook’s server computers, which were not letting people connect to its sites like Instagram and WhatsApp.
It said the problems appeared to be more complex and required some manual updating.
Mike Schroepfer, Facebook’s chief technology officer, 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.”
Data on the web service monitoring platform DownDetector showed that almost 50,000 people had reported the outages on Facebook by just after 5pm.
Most complaints cited issues with the website (72%), while others were linked to issues with the server connection and the app.
Moe than 75,000 had complained about WhatsApp, with 43% reporting issues with the app itself, while 28% cited the server connection and 28% relating to sending messages.
More than 30,000 Instagram users also had similar complaints, with 51% relating to the app, 26% over the server connection and 23% citing the website.
A graph on the DownDetector website showed a clear spike from after 4pm.
Facebook’s share price plummeted 4.9% amid the outage, which also came the day after a whistleblower claimed in a US interview that the company prioritises its own interests over the public good.
The platforms were affected by outages in 2019 – in an incident which saw #FacebookDown, #instagramdown and #whatsappdown trending worldwide on Twitter.
A few months prior, users of Facebook and Instagram reported being unable to open pages or sections on the apps.
Whatsapp said in a statement: “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.”
Instagram said: “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 issue also affected other platforms such as Twitter amid an increase in traffic on its website and app.
Twitter Support tweeted: “Sometimes more people than usual use Twitter. We prepare for these moments, but today things didn’t go exactly as planned.
“Some of you may have had an issue seeing replies and DMs as a result. This has been fixed. Sorry about that!”
It had earlier joked: “Hello literally everyone.”