On October 4 a technical issue took down Facebook, WhatsApp, and Instagram, as well as many of the company's internal systems. Now, Facebook has put out an official statement explaining the cause of the downtime, attributing it to a technical error and clarifying that no third party was involved.

　　"Our engineering teams have learned that configuration changes on the backbone routers that coordinate network traffic between our data centers caused issues that interrupted this communication," Facebook's explanation reads. "This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt."

　　"The underlying cause of this outage also impacted many of the internal tools and systems we use in our day-to-day operations, complicating our attempts to quickly diagnose and resolve the problem," Facebook adds. As the outage was happening, reports suggested that Facebook engineers couldn't communicate due to internal email also going down, and that even security access to Facebook's buildings was affected by the issue.

　　The short version of the explanation is that the outage was caused by "a faulty configuration change on [Facebook's] end." The company has said that there was no malicious activity involved, and that there's no evidence user data was compromised during the downtime.

　　The outage was a sore reminder of how many different services rely on Facebook, with Oculus users unable to access their library of games for the duration, and others losing access to third-party services that are accessed with Facebook logins.