The problem is that the yahoo response does not clearly specify what is wrong in my call. If I somehow know if any of the parameter that I am sending is wrong or there is some specific issue, then I am work to debug that issue.
Any help would be appreciated.
Thanks. The issue is resolved now. The app which I had registered on yahoo was not enabled for reading contacts. Thus, I was not receiving response. I am able to get the proper response now by properly registering new app.
But, yahoo should improve its error response, making it more informative, so that the developer can easily know what is specifically wrong in his/her api call.