Facebook Inc on Monday cited faulty configuration changes on its routers as the root cause of the nearly six-hour outage that prevented the company's 3.5 billion users from accessing its social media and messaging services.

"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 said https://engineering.fb.com/2021/10/04/networking-traffic/outage in a blog post.

  - Reuters