How to enable Distance Matrix API ( Google API ) by restricting access from Android App?

Question

Am using google's distance matric API in my Android Application

https://maps.googleapis.com/maps/api/distancematrix/json?origins=10.016029902612894%2C76.40124697219122&destinations=10.000406199999999%2C76.31017589999999&key=*xxxxxxxxx*

It worked fine until I added a restriction to the API key. Now am getting following error from service.

{
   "destination_addresses" : [],
   "error_message" : "This IP, site or mobile application is not authorized to use this API key. Request received from IP address 178.248.115.115, with empty referer",
   "origin_addresses" : [],
   "rows" : [],
   "status" : "REQUEST_DENIED"
}