Millions around the world found themselves unable to access popular services thanks to a Domain Name System issue with Amazon Web Services.

Amazon Web Services, a cloud computing service run by Amazon, experienced a significant outage that disrupted numerous websites on Oct. 20.

Widespread internet outages were reported early on Monday, taking down popular services including Snapchat, Fortnite and Roblox, as Amazon Web Services said there was an issue they were working to mitigate.

Monday’s Amazon Web Services outage — and the global disruption it caused — underscored just how reliant the internet has become on a small number of core infrastructure providers.

Some Eight Sleep mattress users had a rude awakening after the Amazon Web Services outage, with reports of beds stuck upright and haywire temperatures.

Since a large portion of the internet depends on AWS, the outage cascaded across major firms in disparate industries, leaving some people unable to access airline information or make everyday purchases, Qi Liao, a professor of computer science at Central Michigan University, told ABC News.

Amazon.com cloud service returned to normal operations on Monday afternoon, the company said, after an internet outage that caused global turmoil among thousands of sites, including some of the web's most popular apps like Snapchat and Reddit.

The outage underscored a central trade-off of cloud computing: while it lets businesses deploy global services without maintaining vast infrastructure, it concentrates risk. A problem in a single region—like Northern Virginia—can cause widespread, simultaneous outages for unrelated companies worldwide.

A status page for Amazon's cloud unit showed more than 80 of its services and features were affected early Monday.