We now know why the DNS failed

On October 19, 2025 AWS hit a massive DNS outage that dragged on for more than 24 hours. Ten days later, the official root cause analysis finally dropped, pinpointing failures in the Dynamo service’s DNS setup followed by a cascade of EC2 and Network Load Balancer errors.

The accompanying video breaks it down with timestamps for the summary, the Dynamo DNS meltdown (5:30), EC2 hiccups (13:41) and NLB misfires (16:16). Plus, you get the RCA link and a whole bunch of Hussein Nasser’s backend courses if you’re hungry for more.

Watch on YouTube