You need to check, that geolocation is enabled on the target phone.
Phone's location is determined from several sources: Gps, Wifi and Cell towers.
Gps locations are the most accurate and can have the smallest range accuracy up to 5 meters.
Wifi locations are less accurate and can have values from tens to hundreds of meters.
Cell locations have the lowest accuracy from hundreds to thousands of meters.
Cell locations can come together with the WiFi or Gps locations by it's connection event.
If you are receive only cell locations, it means that the geolocation is disabled
Here is the instructions: