Fastly, the company behind the worldwide outage, said this week that it was the result of a software glitch that occurred when one of its customers changed its settings.
The outage, which occurred on Tuesday, raised questions about the dependence of the Internet service on a small number of infrastructure companies.
The fastly problem caused high-traffic sites to crash, including news sites such as the Guardian and New York Times, as well as British government sites, Reddit and Amazon.
“This outage was widespread and severe, and we truly regret the impact on our customers and everyone who counts on them,” the company said in a blog post written by Nick Rockwell, chief engineering and infrastructure officer, adding that the problem should have been expected.
Fastly operates a suite of servers located in strategic locations around the world to help customers move content and store it close to end users quickly and securely.
The company's blog post gave a timeline of events and promised to check and explain why the software failed to detect bugs.
The company said the bug was in a software update that was shipped to customers on May 12 but did not turn on until an unknown customer made the settings changes that caused the problem "which caused 85% of errors hitting our network."
Soon, engineers noticed the outage occurring at 9:47 GMT, 12:47 GMT, and engineers worked to determine the cause at 10:27 GMT.
Once the settings that were causing the problem were disabled, most of the company's network quickly recovered.
"Within 49 minutes, 95% of our network was operating as normal," the company confirmed.
Fastly said its networks were fully restored at 12:35 GMT, and it began rolling out a permanent software fix at 17:25 GMT.