Many Skype users from Europe to Latin America were not able to use the popular program to make long-distance calls using their computers on Thursday because of a software problem, the company said.
Skype, a division of online auction company eBay Inc, posted on its Web site that many of its users were "having problems" logging into the free service.
"Our engineering team has determined that it's a software issue," a Skype blog posting said by Villu Arak. "We expect this to be resolved within 12 to 24 hours."
A statement from eBay about the outage mirrored the message on Skype's Web site.
It was not immediately clear how many users were affected, but Skype users in Vietnam, Colombia, Brazil, Germany, Finland and the US reported difficulties logging on. Judging from the timing of comments to that posting, some users had been without a service for nearly 20 hours.
By 5am yesterday morning the service was still inaccessible, but Arak, in a new posting on Skype's Web site, said efforts remained underway to restore the program's service.
He also dispelled growing rumors in cyberspace that the program, and the company, had crashed or been the victim of hackers.
"The Skype system has not crashed or been the victim of a cyber attack. We love our customers too much to let that happen," he wrote.
Instead, he said the problem was caused by "a deficiency in an algorithm within Skype networking software. This controls the interaction between the users own Skype client and the rest of the Skype network."
Skype has nearly 220 million accounts but there usually around 5 million to 6 million of them online at any given time. In January, Skype reported that it had counted 9 million users online.
Skype urged users to keep the program running "and as soon as the issue is resolved, you will be logged in. We apologize for the inconvenience."
It also temporarily disabled downloads for the program, but said they would be made available "again as quickly as possible."
There were several posts on Skype's Web site lamenting the lack of connections, some humorous while others contended the outage was caused by something more nefarious, such as hackers.
"My girlfriend is 12,000 miles [19,000km] away and gettin' upset: call in Inspector Gadget to sort this asap, please," said a posting left by a person with the user name timothylegrand.
Another user, duehuynh, wrote: "This is an unexpected surprise, and that explains why we can't log on. Please try to resolve this faster than `12 to 24 hours' as many of us faithful users need Skype for business reasons"
Skype, was founded by Niklas Zennstroem and Janus Friis, and uses peer-to-peer technology to connect calls between its users.