Summary
Our website and production services became unreachable after a network connectivity failure affected our infrastructure in the AWS Asia Pacific (Mumbai) ap-south-1a Availability Zone. We restored production by moving the workload and its existing root volume to ap-south-1b.
Impact
Customers were unable to access the website and production APIs during the incident. No data loss or disk corruption was identified.
Root cause
The evidence isolates the failure to the AWS-managed networking data plane serving our infrastructure in ap-south-1a. DNS resolution through AmazonProvidedDNS, inbound connectivity, outbound HTTPS and AWS Systems Manager connectivity failed, while the EC2 instance, operating system, storage and applications remained healthy.
The same failures occurred after moving to different EC2 hardware and on a new control instance in an independent subnet within ap-south-1a. An equivalent control instance in ap-south-1b worked normally. No customer-side route, network ACL, security group, DHCP, resolver, network interface or internet gateway changes occurred during the failure window.
AWS has not yet confirmed which internal networking component failed. The incident has been reported to AWS under case case-386503255471-muen-2026-2b01f97a42ca94f8.
Resolution
We moved the production to a replacement instance in ap-south-1b, reassociated the production Elastic IP and validated the website, APIs and all production services before declaring the incident resolved.