A massive internet outage has affected websites including the Guardian, the UK government’s website gov.uk, Amazon and Reddit. The issue made the sites inaccessible to many users for more than an hour on Tuesday morning.
The outage has been traced to a failure in a content delivery network (CDN) run by Fastly. It began around 11am UK time, and saw visitors to a vast array of sites receive error messages including, “Error 503 service unavailable” and a terse “connection failure”.
Others affected included publishers, CNN, the New York Times, and the Financial Times as well as the streaming services Twitch and Hulu.
As well as bringing down some websites entirely, the failure also broke specific sections of other services, such as the servers for Twitter that host the social network’s emojis.
Fastly, a cloud computing services provider, was believed to be the cause of the problem. The company runs an “edge cloud”, which is designed to speed up loading times for websites, protect them from denial-of-service attacks, and help them deal with bursts of traffic.
But that technology requires Fastly to sit between most of its clients and their users. That means that if the service suffers a catastrophic failure, it can prevent those companies from operating on the net at all.
In an error message posted at 10.58 UK time, Fastly said: “We’re currently investigating potential impact to performance with our CDN services.” The company did not respond to a request for comment from the Guardian.
The increasing centralisation of internet infrastructure in the hands of a few large companies means that single points of failure can result in sweeping outages. A 2017 problem at Amazon’s AWS hosting business, for instance, took out some of the world’s biggest websites for several hours across the entire US east coast, while a 2020 problem with Cloudflare, another CDN company, led to a half-hour outage for most of the internet in major cities across Europe and the Americas.