It looks like there are some problems with Skype since yesterday in many countries on the world.
Skype is not working in UAE and others Gulf countries.
This problem is also present in many others countries on all continents.
Skype not working!
Skype not connecting!
Skype not responding!
Skype not singing in!
These are the most frequent issues people descibe.
This problem was confirmed by official Skype support:
“We are aware of an issue affecting Skype status at the moment, and are working on a quick fix.”
“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. The issue did not affect Skype for Business users.” (source)
We’ll be waiting for resolving this issue and inform you when everything be fixed.