Some of the world's most popular social networks went down on Tuesday morning (NZ time), with Facebook, Whatsapp and Instagram going offline for users around the world.
The outage was one of the longest to ever hit the social media networks, Reuters reported, with access to some services starting to be restored around 10.45am NZ time.
A Facebook spokesperson apologies to all those affected by the platform outages.
"We’re sorry. We know billions of people and businesses around the world depend on our products and services to stay connected," they said.
"We appreciate your patience as we come back online."
That was made more complicated after The New York Times reported the outage had impacted the ability of some employees to access buildings because their badges has stopped working.
Tech site The Verge reported Oculus VR, the company's virtual reality arm, also went offline. As part of Facebook, Messenger was also down.
It also reported some employees of the social media giant had taken to external email accounts as it's internal email wasn't working.
Facebook was inaccessible because users were not being directed to the correct place by the Domain Name System. Facebook itself controls the relevant settings.
DNS allows web addresses to take users to their destinations. A similar outage at cloud company Akamai took down multiple websites in July.
Security experts tracking the situation said the outage likely was triggered by a configuration error that left directions to Facebook servers unavailable. That could be the result of an internal mistake, though sabotage by an insider would be theoretically possible.
An outside hack was viewed as less likely. A massive denial-of-service attack that could overwhelm one of the world's most popular sites, on the other hand, would require either coordination among powerful criminal groups or a very innovative technique.
Facebook said the outage was caused by a networking issues interrupting communications between data centres.
With communications not working properly the problems cascaded causing outages across the systems.
It said no user data was compromised as a result of the incident.
All the services went offline as Facebook global head of safety Antigone Davis was live on TV in the US defending the company over accusations its Instagram service is harmful to teenage girls, The Verge said.
Facebook shares fell 5.3 percent in afternoon trading in the US.
The social media giant experienced similar widespread outages with its suite of apps this year in March and July.
With its main rival down, Twitter appears to be enjoying the attention - tweeting "hello literally everyone" from its own account.
