Using Skype API to make call c#

I am trying to making call programmatically through Skype. Skype is installed in my PC but when I am trying to make call through Skype API & C# then every time I am getting a exception calledConnection refuse and I am not being able to fix it. So, looking for proper guide to solve the issue.

Here is code snippet by which I am trying to make call programmatically.

Skype skype;
        skype =new SKYPE4COMLib.Skype();stringSkypeID="+222222222";Call call = skype.PlaceCall(SkypeID);do{System.Threading.Thread.Sleep(1);}while(call.Status!=TCallStatus.clsInProgress);

Please guide me what is missing in my code. Thanks