Tuesday evening, Facebook revealed in a blog post the reason behind the collapse of its global social networking system.

The company said that routine maintenance was the cause of the collapse that lasted for over six hours on Monday, effectively blocking billions of users from accessing Facebook, Instagram and WhatsApp.

Facebook explained that its engineers inadvertently canceled all connections in its network, “effectively disconnecting Facebook's data centers globally.”

This also caused employees to lose access to internal tools, including those used by its programmers, to correct such issues, according to the company.

Also Read: Facebook, WhatsApp, Instagram experience outage worldwide

Facebook added that the program's audit tool had a glitch and failed to stop the command that caused the outage.

This comes after Facebook and its subsidiaries faced a malfunction on Monday that is considered the largest in the company's history.

Facebook said earlier Tuesday that the main reason behind the outage that occurred Monday evening was a configuration change to the main routers which coordinate network traffic between the company’s data centers.

At around 1:46am Tuesday, Mike Schroepfer, a CTO at Facebook wrote on Twitter “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.”

In a statement, Facebook said that they have no evidence that user data has been leaked as a result of the outage.

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