Skype users are reporting disruptions to their service as the Microsoft-owned messaging platform is hit by a global outage.
Users affected are unable to change their status or start calls with their contacts, which all show as offline.
However, users of the web version of Skype were unaffected.
According to downdetector.com, the problems appear to be most prevalent in the UK and Japan, although they were reported in countries across all regions of the world.
"We are aware of an issue affecting Skype status at the moment, and are working on a quick fix," the Skype Support account Tweeted.
"Some of you may experience problems with Skype presence and may not see online. We have detected an issue with the status settings of Skype," wrote Leonas Sendrauskas, web quality assurance engineer for Skype in a blog.
"Affected users will not be able to change their status, their contacts will all show as offline and they will be unable to start Skype calls to them."
Sendrauskas added that Skype was "working on a fix for this issue" but did not give details about when the promised update would arrive.
The Skype problems are not the only significant recent outage; services such as Tinder and Netflix were down this weekend after a server fault knocked out Amazon Web Services.