Unable to Send Skype message through Excel VBA

[alijaveed]

Hi Everyone,
I want to write macro to send messages in Skype. And I found below coding but I am getting an error message as "Wait timeout" while running below macro

Sub testingskype()
Dim aSkype As SKYPE4COMLib.Skype
Set aSkype = New SKYPE4COMLib.Skype
Dim oChat As Chat
Dim skUser As SKYPE4COMLib.User
Set skUser = aSkype.User("user_name")

Set oChat = aSkype.CreateChatWith(skUser.Handle) <----{ Error message on this line}

oChat.OpenWindow
oChat.SendMessage "hello.....testing"
End Sub

Please help me resolve this issue.
Thanks in advance.