Returns null Location using Fused Location provider in android

Question

I am using Samsung gaylaxy Y SCH-1509 android version 2.3,Gingerbird

I am using a Fused location provider to fetch the coordinates , it works fine for me

it is same as that http://www.blogosfera.co.uk/2013/08/fused-location-provider-in-android/

But the issue is after 2-3 days it stop giving me the location but after a day it again start giving me the location (CONFUSED :X)

Fused location provider uses :- Wi-fi ,GPS, Network,Sensors Correct?

This Link Says LocationClient getLastLocation() return null you should have wifi gps enabled to fetch the coordinates

I have enabled Wi-Fi ,GPS , Network but i still get a null location

Q1} What should be the Google Apps Settings ..?.

Q2) What can be the cause for it ? which coordiantes do get first while using Fused , how does it stop in getting the coordinates when it is working fine.