This can due to mainly 3 reasons as mentioned below:
Location Permission Not Given: You may not have granted permission to access your location. You can go the give this permission by visiting the setting section of your phone.
Location Service Disabled: You may have turned off your location services. You can turn off your location services from the setting section of your phone or your phone menu depending upon your handset make and model.
Poor Coverage: If the permission has been given, we access your current location by using the location provided by your phone. For this suitable network coverage is required. There might be a temporary network issue at your location or the location may have a poor network.