Solution 1: Get updated version
First make sure to install a new version of Skype.Open your skype go to > Help > Check for updates.Just follow the process.
Solution 2 : Try old stable version
If the new version doesn't help, reinstall it and get the older version here:
After installing this version, make sure to disable the Automatic updates:
Tools -> Options -> Advanced -> Automatic updates ->Turn off automatic updates
Solution 3 : Deleting Skype DbTemp Folder
Go to Windows Start and in the Search/Run box type %temp%\skype and then press Enter or click the OK button. Delete the DbTemp folder.
Solution 4: Skype Reset
Terminate the skype app.In your the run menu type in : %appdata% then, hit enter. Rename Skype to Skypeold. Restart Skype and see if the problem is resolved.
Solution 5: Run Skype as Administrator
Sometimes Windows UAC blocking sort of necessary process Skype has to run. Find the skype icon in your desktop, right click select Properties, Compatibility tab, Change Settings For All Users, Run
This Program As Administrator.
Solution 6 : Turn off Antivirus Firewall
If you have McAfee / Norton Antivirus installed in your system try to enabling / disabling its Firewall feature.Sometimes the firewall block Skype connections or any other program unnoticed.
I hope these options will work for you.