Facebook and Instagram came back online on early Tuesday morning, Oct. 5 before 6am (Singapore time), following a massive global outage that lasted nearly six hours.

Facebook, Instagram and WhatsApp -- all belonging to the same company -- were hit by the largest such failure ever with 10.6 million problem reports globally on Downdetector, a website monitoring group.

Partial access to these platforms were reinstated initially.

Facebook sorry

The initial stages of the outage saw Facebook's chief technology officer apologise publicly.

"To every small and large business, family, and individual who depends on us, I'm sorry," Facebook Chief Technology Officer Mike Schroepfer tweeted, adding that it "may take some time to get to 100 per cent".

*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

— Mike Schroepfer (@schrep) October 4, 2021

Facebook services coming back online now - may take some time to get to 100%. To every small and large business, family, and individual who depends on us, I'm sorry.

— Mike Schroepfer (@schrep) October 4, 2021

To the huge community of people and businesses around the world who depend on us: we're sorry. 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.

— Meta (@Meta) October 4, 2021

Facebook has since apologised and provided an update that the outage was due to a "faulty configuration change".

More info on the outage today: https://t.co/D54G0PLaqk

— Mike Schroepfer (@schrep) October 5, 2021

"To all the people and businesses around the world who depend on us, we are sorry for the inconvenience caused by today’s outage across our platforms," a statement by Vice President of Engineering and Infrastructure Santosh Janardhan said.

"We want to make clear at this time we believe the root cause of this outage was a faulty configuration change. We also have no evidence that user data was compromised as a result of this downtime."

Outage likely an internal mistake

Before Facebook's update, security experts said the disruption could be the result of an internal mistake, though sabotage by an insider would be theoretically possible.

Facebook acknowledged users were having trouble accessing its apps initially during the outage, but did not provide any specifics about the nature of the problem or say how many users were affected.

The error message on Facebook's webpage suggested an error in the Domain Name System (DNS), which allows web addresses to take users to their destinations.

News agencies reported that several Facebook employees who declined to be named said they believed that the outage was caused by an internal routing mistake to an internet domain that was compounded by the failures of internal communication tools and other resources that depend on that same domain in order to work.

One observer described the situation as being locked out of one's own car and having to manually overwrite the system to regain access.

https://twitter.com/alexhern/status/1445130869308538887

The social media giant was losing about US$545,000 in US ad revenue per hour during the outage, according to estimates from ad measurement firm Standard Media Index.

Facebook is the second largest digital advertising platform in the world.

Top photo via Unsplash