(Reuters) -An outage at Amazon's ( AMZN ) cloud computing unit was gradually easing on Monday, after disrupting many online services offered by banks, social media companies and businesses.

The turmoil marked the largest internet disruption since last year's CrowdStrike malfunction hobbled tech systems in hospitals, banks and airports. It highlights the vulnerability of the world's interconnected technologies.

The cloud unit, Amazon Web Services, or AWS, has more than one million active customers every month and it currently spans 120 availability zones across 38 geographic regions, according to the company website.

Below are key details about the outage:

CAUSE OF ISSUE

The outage began when a problem with the Domain Name System prevented applications from finding the correct address for the DynamoDB API, which is a cloud database that many online services use to store user information and other critical data.

The internet uses DNS like a phone book to turn names into numeric addresses as computers require an IP address to connect to the right server.

Apps could not look up the IP address for DynamoDB's API due to the DNS problem.

AWS said the issue originated from within the elastic compute cloud (EC2) internal network, the high-speed network that AWS uses to connect all its cloud services within the data centers of the US-EAST-1 region.

PLACE OF ISSUE

AWS said on its status page that Monday's outage originated at its US-EAST-1 location in northern Virginia.

AWS hosts its cloud infrastructure at US-EAST-1, which is one of the most prominently used AWS locations. The US-EAST-1 site is often the default region for many AWS services, according to the AWS website.

PREVIOUS OUTAGES

June 2023

A capacity management issue in the US-EAST-1 region affected the AWS Lambda service that lets customers run computer programs without having to manage any underlying servers and other interdependent services. Many applications were impacted for hours.

December 2021

An internal automated system in US-EAST-1 unexpectedly triggered a network congestion event, overwhelming network devices. It caused a widespread outage for several hours, hitting services, including Ring security cameras, mobile banking app Chime and robot vacuum cleaner maker iRobot, which use AWS.

BY THE NUMBERS

AWS' revenue grew 18% from a year earlier to $30.9 billion for the second quarter ended June 30.

SERVICES AFFECTED

E-commerce and retail

** Amazon ( AMZN )

Streaming and media

** Prime Video

** Crunchyroll

Gaming

** Roblox

** Epic Games' Fortnite

Social media and communications

** Snapchat

** Reddit ( RDDT )

** Signal

Finance and payments

** PayPal's ( PYPL ) Venmo

** Robinhood

** Lloyd's Banking Group

Transport

** Lyft ( LYFT )

Artificial intelligence

** Perplexity

Education/Productivity

** Duolingo ( DUOL )

Source for services hit: Downdetector.com