Go Daddy, one of the world's biggest Internet hosting firms, said that some customer web sites and email accounts went down on Monday. An anonymous hacker claimed responsibility for the service disruption.
It was not clear how many customers were affected by the outage. The website of Scottsdale, Arizona-based company was inaccessible late on Monday afternoon.
"Hey all. We're aware of the trouble people are having with our site. We're working on it," the Scottsdale, Arizona, company said via Twitter on Monday afternoon. It did not explain the cause of the outage and company officials could not be reached.
Later in the afternoon, the company that targets its products at small businesses said via Twitter that "Some service has already been restored. Stick with us."
Somebody using the handle "Anonymous Own3r" claimed responsibility for the outage via Twitter, saying it was the work of one person and not a group.
Go Daddy describes itself as the world's largest web hosting company and also the top provider of domain names.
(Reporting By Noel Randewich and Jim Finkle; Editing by Tim Dobbyn and Andrew Hay)