The websites of several high-profile companies including HSBC, Airbnb and British Airways were hit by internet outages.
The incident may be linked to US firm Akamai Technologies, a content delivery network, which said the issue was not the result of a cyber attack on their platform.
A message on the BA website read: “Service Unavailable – DNS failure. The server is temporarily unable to service your request. Please try again later.”
And a message on Airbnb’s site said: “This site can’t be reached.”
We have implemented a fix for this issue, and based on current observations, the service is resuming normal operations. We will continue to monitor to ensure that the impact has been fully mitigated.
— Akamai Technologies (@Akamai) July 22, 2021
HSBC’s website had a similar message.
The sites were accessible again about half an hour after the issues were first reported around 5pm in the UK.
And there are reports other airlines and major companies are also affected, as well as the 911 service on the east coast of the US.
It is not known exactly what caused the issues. However, Akamai reported problems with its Edge DNS Service.
It later confirmed a fix for its services had been implemented.
A tweet added: “We are continuing to monitor the situation and can confirm this was not a result of a cyberattack on the Akamai platform.”
Edge DNS is a content delivery network (CDN), providing a similar service to Cloudflare, Amazon CloudFront or Fastly.
CDNs speed up the internet by keeping copies of websites’ data in various locations around the world, so computers do not have to wait for long periods of time to talk to sites on the other side of the world.
Last month, large parts of the internet went down when CDN Fastly began experiencing issues.
US-based Fastly said the issues on 8 June were down to an “undiscovered software bug” in its system which was triggered by a single unnamed customer who updated their settings.