There is an issue with Skype currently whereby users cannot sign into the service. This has been posted up on the Skype Heartbeat webpage at https://support.skype.com/en/status and this is the data from the webpage.
Limited service of Signing into Skype
We have identified an incident affecting our services and are actively looking into it.
January 24, 2018 11:55 PM by Jagadish
January 24, 2018 04:54 PM
Affected services: Signing into Skype
Some users might be experiencing problems when signing in to Skype. There might be error messages about connection issues or incorrect credentials.