Phone Call functionality is not working in iOS

ionic-v1
1

Implemented Phone Call functionality. It works well with Android device but same thing not working in iOS.

Tried
window.plugins.CallNumber.callNumber(onSuccess, onError, contactNum, true);
and
window.plugins.phoneDialer.dial(contactNum);

also added below lines in Config.xml but still no luck.

Please let me know what is blocking in iOS to make call.