Skype is still suffering from a major outage as the service fails to send messages or recognise users' presence on the site. Both Mac and Windows clients are affected by the issue.

The firm said late on the afternoon of Monday, 21 September, that it had found the root cause of the issue and was now hoping to get the service back to normal.

"We have identified the network issue which prevented users from logging in and using Skype today. We're in the process of reconnecting our users, and focused on restoring full service," wrote web quality assurance engineer Leonas Sendrauskas.

It was also confirmed that Skype for Business users were not affected by the outage.

Despite finding the causing of the fix the service is still patchy, with users' status information not showing and group chats still not working.

The outage began early on Monday and Skype said it was aware of the issue in a blog post, although did not give any indication of the cause.

“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 web quality assurance engineer Leonas Sendrauskas.

“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.

Skype also confirmed the outage on Twitter, but gave no more explanation as to the cause.