Everyone makes mistakes. But working at Amazon Web Services means an incorrectly entered input can lead to a massive outage that cripples popular websites and services. That’s apparently what happened earlier this week, when the AWS Simple Storage Service (S3) in the provider’s Northern Virginia region experienced an .

Other Amazon services in the US-EAST-1 region that rely on S3, like Elastic Block Store, Lambda, and the new instance launch for the Elastic Compute Cloud infrastructure-as-a-service offering were all impacted by the outage.

AWS apologized for the incident in a . The outage affected the likes of Netflix, Reddit, Adobe, and Imgur. More than half of the top 100 online retail sites experienced slower load times during the outage, website monitoring service .

Here’s what set off the outage, and what Amazon plans to do: