GoDaddy, a popular Web site hosting company, said on Tuesday that its extensive service interruptions on Monday were the result of technical problems, not a cyberattack as one hacker has claimed.

Scott Wagner, the company’s interim chief executive, said failures that knocked out several million Web sites were caused by an internal network error, “not a hack.”

That explanation contradicted claims by a supporter of Anonymous, the loose confederation of rogue hackers, who said on Twitter Monday that he took down GoDaddy using a distributed denial of service attack, or DDoS attack. In a DDoS attack, hackers barrage a site with traffic until it collapses under the load.

It was the second time this month that hackers claiming affiliation with Anonymous appeared to be falsely claiming credit for hacks. “We’re starting to see a pattern of Anonymous taking credit for the media attention,” said Rob Rachwald, director of security at Imperva, a computer security firm. “There has been a lack of serious Anonymous campaigns in the last several months, and they may be trying to get back in the groove after a temporary lull.”

GoDaddy was emphatic that the failure was not caused by outsiders. “It was not a ‘hack’ and it was not a denial of service attack,” Mr. Wagner said. While he was not specific, he said “internal network events” corrupted router data tables.

GoDaddy’s Web site was down for several hours on Monday afternoon, as were several million Web sites that use it for domain hosting and other services. GoDaddy manages 53 million domain names and hosts roughly five million Web sites on its servers. Its shutdown caused a “ripple effect” across the Internet, said Stephen Pierzchala, an analyst at Compuware, a firm that measures Internet performance.

The hacker who initially claimed credit for the GoDaddy failure posted on Tuesday what he said was GoDaddy’s source code to Pastebin, a Web site. But that same code had appeared online in a software forum two years ago.

In a direct message, the person behind @Anonyops, a Twitter account frequently associated with the Anonymous movement, said the hacker was either “misguided or trying to give Anons a bad reputation.”

Last week an Anonymous-related group released a file it said contained a million ID numbers for Apple mobile devices obtained by hacking into the computer of an F.B.I. agent. The data was actually stolen from a Florida company.