Likely referring to the February 28th, 2017 S3 Service Disruption in the Northern Virginia (US-EAST-1) Region, for which Amazon published a postmortem at https:

Likely referring to the February 28th, 2017 S3 Service Disruption in the Northern Virginia (US-EAST-1) Region, for which Amazon published a postmortem at https://aws.amazon.com/message/41926/ https://aws.amazon.com/message/41926/