API setup and example

Hi All here,

I am new to suiteCRM here. I am trying to get access to API V8 using postman where I can disable ssl.
Now I can use my localhost url http://localhost/newCRM in the curl url.
Rest everything same. But still I am unable to generate the token…Here is my code

<?php 

$url = 'http://localhost/newCRM/Api/access_token';
$ch = curl_init($url);

$headers = [
    'Accept: application/vnd.api+json',
    'Content-Type: application/vnd.api+json',
    'cache-control: no-cache'
];

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_VERBOSE, true);
curl_setopt($ch, CURLOPT_HEADER,true);

$post = array(
    "grant_type" => 'client_credentials',
    "client_id" => "1cf78634-0fd2-1ca6-432f-5f352d2b3c2b",
    "client_secret" => "Admin@55"
);

curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($post));
$response = curl_exec($ch);
$header_size = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
$header = substr($response, 0, $header_size);
$body = substr($response, $header_size);

curl_close($ch);
print_r($response);