Amazon web services return after global outage - but what went wrong?

Amazon Web Services (AWS) says it has resolved Monday’s global outage, which led to disruption across a wide range of internet services, including HMRC, Halifax and Lloyds.

The issues affected people around the world trying to connect to online services used for work, social media and gaming.

What is Amazon Web Services?

AWS is the world’s largest cloud computing provider and offers a wide variety of services, including storage, databases, machine learning, and security tools.

It provides behind-the-scenes cloud computing infrastructure to many government departments, universities and businesses.

Seattle-based Amazon said the problems were centered in its Virginia-based US-EAST-1 data center region, one of its most important cloud hubs around the world.

What happened?

AWS traced the source of the problem to something called the ‘DynamoDB endpoint in the US-East-1 Region’.

DynamoDB is a centralized database service that many internet-based services use to track user information, store key data and manage their operations.

Amazon suggests the problem isn’t with the database itself, but rather that something went wrong with the records that tell other systems where to find their data.

Because so many sites and services use AWS, a DNS (Domain Name System) error can have widespread results.

Professor Oli Buckley, an expert in cyber security at Loughborough University, said that DNS acted like “a phone book for the internet” by telling devices where they needed to go to find a particular service.

He said that a DNS error can cause thousands of systems to slow down as they attempt to locate the service until they “eventually just stop trying”.

Screengrab of the website for HMRC. / Credit: PA

Who was affected?

Downdetector, a website which tracks complaints about online services, showed a spike in reports on Monday, with thousands reporting outages at Amazon Web Services (AWS), HM Revenue & Customs (HMRC) as well as at Snapchat, Starbucks, Slack and Ring.

Customers also reported an increase in outage reports at UK banks including Lloyds, Halifax, and Bank of Scotland, with 6,925 Downdetector outage reports at Lloyds at 9.31am.

Gaming platforms Roblox and Fortnite were also affected.

A spokesperson for VodafoneThree said that although its networks were “operating normally” the outages had affected some of its apps and websites.

Has this happened in the past?

This is not the first time a problem with Amazon’s key services has caused widespread disruptions.

Many popular internet services and publishers were down after a brief outage in 2023.

AWS’s longest outage in recent history occurred in late 2021, when companies (everything from airline reservations and auto dealerships to payment apps and video streaming services) were affected for more than five hours.

Other major outages happened in 2020 and 2017.

Unrelated to Amazon, a faulty software update by cybersecurity company CrowdStrike affecting devices running Microsoft’s Windows also rippled across the world to cause massive disruptions in 2024.