AWS Resolves Major Outage After Nearly 24 Hours of Service Disruption

Amazon Web Services experienced a significant service disruption in its US-EAST-1 region that lasted nearly 24 hours, affecting over 140 services and causing widespread issues for customers worldwide.

The outage began late on October 19, 2025, and was fully resolved by the afternoon of October 20.

Root Cause Identified as DNS Resolution Issue

The incident started at approximately 11:49 PM PDT on October 19, when AWS engineers detected increased error rates and latencies across multiple services in the critical US-EAST-1 region.

At 12:26 AM on October 20, AWS identified the trigger as DNS resolution issues affecting regional DynamoDB service endpoints. This initial problem created a cascading failure that impacted numerous other services.

After resolving the DynamoDB DNS issue at 2:24 AM, AWS faced a subsequent impairment in EC2’s internal subsystem responsible for launching new instances due to its dependency on DynamoDB.

The situation escalated further when ...