We now know why AWS’s DNS went down

On October 19, 2025, AWS suffered a massive, day-long DNS outage that knocked services like DynamoDB, EC2 and Network Load Balancers offline. Ten days later, the official root cause analysis revealed that a configuration glitch in DynamoDB’s DNS setup cascaded into widespread failures across AWS’s infrastructure.

The accompanying deep-dive video timestamps walk you through the key moments—starting with a high-level summary, then exploring how DynamoDB lost its DNS, the resulting EC2 errors, and finally the network load balancer breakdown. Check out the full RCA on AWS’s site.

Watch on YouTube