Many popular websites fell offline on Thursday in a widespread global outage of service.
Visitors attempting to reach some sites received DNS errors, meaning their requests could not reach the websites.
Affected services included HSBC bank, British Airways and the PlayStation network used for online games.
Internet outage monitoring platform DownDetector reported thousands of problems from its users across dozens of hugely popular sites.
The cause of the problem is not yet clear.
However, one hugely popular DNS provider, Akamai, reported "an emerging issue" with its Edge DNS service.
"We are actively investigating the issue," it said.
However, it said the issue was a "partial outage" - and some users reported being able to access some compromised services in different regions.
Visitors attempting to reach some sites received DNS errors, meaning their requests could not reach the websites.
Affected services included HSBC bank, British Airways and the PlayStation network used for online games.
Internet outage monitoring platform DownDetector reported thousands of problems from its users across dozens of hugely popular sites.
The cause of the problem is not yet clear.
However, one hugely popular DNS provider, Akamai, reported "an emerging issue" with its Edge DNS service.
"We are actively investigating the issue," it said.
However, it said the issue was a "partial outage" - and some users reported being able to access some compromised services in different regions.
Major websites hit by global outage
The websites of HSBC, British Airways and Airbnb are among those to have briefly gone offline.
www.bbc.co.uk
