On Monday, Facebook and several other related sites experienced a prolonged outage, lasting roughly six to seven hours. Following hundreds of thousands of reports worldwide, Facebook addressed the issue Monday afternoon, noting that changes made to the backend of its systems were the primary source of the outage. “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… This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt,” Santosh Janardhan, vice president of infrastructure at Facebook, wrote in the apology. The outage followed Sunday evening’s interview with Frances Haugen, a former Facebook employee who came out about the company’s practices and how it perpetuates hateful and toxic stories to help drive engagement. Facebook says it believes the only cause of the outage was the changes made to the router system it uses to coordinate network data, and that there is no evidence user data was compromised in any way as a result.