June 9, 2021: -Reddit and global news websites, including the Financial Times, New York Times, and Bloomberg, experienced intermittent outages on Tuesday, with some users unable to access the sites.

Some visitors to the websites in the U.K. and the U.S. received the message “Error 503 Service Unavailable.”

According to reports, Amazon, Twitter, PayPal, Spotify, Twitch, the BBC, and The Guardian were also affected. The Verge used an open Google Doc to report on the story, although it forgot to turn to edit off.

The first reports of the outage began around 6 a.m. E.T., but for sites mainly was back online for users an hour later. But some places, including the U.K. government website gov. the U.K., and The New York Times, experienced slow loading times and graphics issues.

U.S. cloud computing services provider Fastly said on its website at 5:58 a.m. E.T. that it was investigating a technical issue. At 6:44 a.m. ET moreover said that the issue had been identified and “a fix is being implemented.” At 8:41 a.m. ET, Fastly said the issue had been resolved. Fastly’s stock was decreased 1.6% in premarket trading after the outage began. At one point, it was down nearly 3%.

Fastly operates a content delivery network. A CDN is a network of servers and data centers worldwide that enable the transfer of assets needed for loading Internet content such as HTML pages, JavaScript files, images, and videos.

A relatively small number of companies operate the infrastructure that underpins much of the internet. When one of them has a problem, it can lead to widespread global outages that affect billions.

“This is what happens when half of the internet relies on Goliaths such as Amazon, Google, and Fastly for all of its servers and web services,” Gaz Jones, technical director of digital agency Think3, said. “The entire internet has become dangerously geared on just a few players.”

When Amazon’s cloud computing division, Amazon Web Services, encountered an issue in 2017, some of the world’s biggest websites went offline for several hours across the whole U.S. East Coast. In 2019, Cloudflare, another CDN firm, experienced a problem that lasted around an hour and affected websites, which include chat service Discord and the dating site OkCupid.

Toby Stephenson, chief technology officer at I.T. and cybersecurity company Neuways, agreed that the incident “highlights the reliance of many of the biggest websites from all over the world on content delivery networks.”

“As there are so few of these CDN services, these outages can occur from time to time,” he said.