Geolocation code returning an empty result - geolocation

Question

I want to get the device longitude and latitude using the mac address not it's not returning any value.
I have activate my Google Geolocation API and have enable billing. pls help.
<?php
$mac = "E4:D5:3D:E4:05:BF";
//encode the data in JSON
$wifiAccessPoints = array("macAddress"=>$mac);
$wifiAccessPoints = json_encode($wifiAccessPoints);
$API_key = "AIzaSyApOf.................";
$url = "https://www.googleapis.com/geolocation/v1/geolocate?key=$API_key";
$client = curl_init($url);
//send the request to resource
curl_setopt($client, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($client, CURLOPT_HEADER, false);
curl_setopt($client, CURLOPT_POSTFIELDS, $wifiAccessPoints);
curl_setopt($client, CURLOPT_RETURNTRANSFER,true);
curl_setopt($client, CURLOPT_HTTPHEADER,array("Content-type: application/json", "Content-Length".strlen($wifiAccessPoints)));
curl_setopt($client,CURLOPT_POST,true);
//get response from request.
$response = curl_exec($client);
//decode format response
//$result = json_decode($response);
$status = curl_getinfo($client, CURLINFO_HTTP_CODE);
echo $status."<br>";
echo $response."<br>";
?>

Answer 1

The error being returned indicates that your request is formatted correctly, but the API could not find a geolocation for it. The API documentation has this to say about your result:
Reason: notFound
Domain: geolocation
Status Code: 404
Description: The request was valid, but no results were returned.
So it appears that you are performing your request successfully, but Google will not always be able to tell you where a particular WiFi access point is located (t would be impossible to expect them to know them all).
The documentation also states that
The request body's wifiAccessPoints array must contain two or more WiFi access point objects. macAddress is required; all other fields are optional.
It looks like you only have one access point, a lookup by IP may be ore accurate. The documentation has a wealth of information on how you can reformat your input JSON.