Facebook and Instagram back online after 14-hour outage - here's what happened

Facebook, Instagram and WhatsApp are all back online and working as normal after a 14-hour outage left many users unable to post updates.

Facebook and Instagram both started experiencing difficulty at around 4pm GMT on March 13, according to data from website Downdetector, which monitors online outages.

Error messages on both sites stated: "Oops... Something went wrong. We're working on getting it fixed as soon as we can."

Many users took to other social networks such as Twitter to vent their frustration at being unable to access the online services.

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The hashtags #FacebookDown and #InstagramDown were used more than 150,000 times.

WhatsApp users also started reporting issues from around 6pm GMT, with some users claiming they were unable to send messages.

Responding to rumours posted on other social networks, Facebook said the outages were not a result of a cyber attack.

"We're aware that some people are currently having trouble accessing the Facebook family of apps," Facebook said in a statement sent to Mirror Online at 7pm last night.

"We're focused on working to resolve the issue as soon as possible, but can confirm the issue is not related to a DDoS attack."

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A DDoS (Distributed Denial of Service) is a type of cyber attack that involves flooding a website with extremely high volumes of traffic.

Facebook has not yet provided a further update, but at 4.40am this morning, Instagram tweeted an image of Oprah Winfrey screaming with the caption: "Anddddd... we're back."

The outage has been described as Facebook's "most severe in history".

The last time Facebook had a disruption of this magnitude was in 2008, when the site had 150 million users - compared with around 2.3 billion monthly users today.

It is not yet clear what caused the issues for users of the social network around the world, but one internal source told NBC Bay Area that Facebook's its database was "overloaded".

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"We are racing to spin up new machines as others go down. Mostly resolved... but it takes time," the source said.

Network monitoring company ThousandEyes, which claims to act as the "X-Ray machine of the Internet", said that the cause appeared to be internal rather than a network or Internet delivery issue.

"Given the sheer scale and continuous changes that these web scale providers are constantly making to their applications and infrastructure, sometimes things break as a result of these changes, even in the most capable hands," a spokesperson for the company said.

ThousandEyes added that it had not seen any significant changes to the Border Gateway Protocol (BGP), which manages how packets are routed across the internet .

"Since Facebook uses its own backbone network, it's not clear how an external transit route issue would cause a disruption within the internal Facebook network," the spokesperson said.

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Facebook, which gets much its revenue from advertising, is still investigating the overall impact of the outages, "including the possibility of refunds for advertisers".

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