The platforms confirmed that they were aware of issues and are working to resolve them.
Shortly before midnight, Instagram and Facebook appeared to be working again. However, users were still experiencing issues with WhatsApp.
Facebook issued an apology for the outage. “To the huge community of people and businesses around the world who depend on us: we’re sorry,” it 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.”
According to web service monitoring platform DownDetector, thousands of people reported outages before 5pm. Data on its website showed that almost 50,000 people had reported the outages on Facebook.
Most complaints cited issues with the website (72 per cent), while others were linked to issues with the server connection and the app.
— Jordan (@snkrsthechef) October 4, 2021
More than 75,000 had complained about WhatsApp, with 43 per cent reporting issues with the app itself, while 28 per cent cited the server connection and 28% relating to sending messages.
More than 30,000 Instagram users also had similar complaints, with 51 per cent relating to the app, 26% over the server connection and 23 pre cent citing the website.
A graph on the DownDetector website showed a clear spike from after 4pm.
Many people vented on Twitter about their struggle to try to use their other social media accounts.
Quickly it begun trending when people realised they were all suffering with the same problem and many shared memes about their experience.
Among the sea of comments, one person wrote: “I thought my wifi is not working properly then I switched to mobile data still not working, Now on twitter I got to know #WhatsApp is down.”
— lilly🕊️♡ (@With_GOTseven7) October 4, 2021
Another wrote: “Whole nation coming to Twitter to check whether Whatsapp and Instagram are working or not yet #whatsappdown#instagramdown.”
“Instagram and what’s app not working AGAIN #instagramdown#whatsapp down.”
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 said: “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.
Whatsapp said on Twitter: “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.”