Microsoft's video chat service Skype currently suffers from a worldwide outage. 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.
Text chats to users that appear to be offline are still possible and both desktop and mobile versions of Skype are affected. The browser based version of Skype appears to work without issues.
In a status update Microsoft writes, "We're working on a fix for this issue and hope to have an update for you soon. Please accept our apologies for any inconvenience caused while we get this resolved."
