AppStore connect API 401 ERROR, while using Firebase\JWT

I am trying to get reports and data from AppleStore connect API, but it keeps giving me 401 ERROR.

{ "errors": [{ "status": "401", "code": "NOT_AUTHORIZED", "title": "Authentication credentials are missing or invalid.", "detail": "Provide a properly configured and signed bearer token, and make sure that it has not expired. Learn more about Generating Tokens for API Requests }] }

I was using the guidelines from generating_tokens_for_api_requests, guidelines and using firebase/php-jwt library for PHP to create jwt token for the Auth. I am using guzzle for sending the API request. In the App store the key has Developer access privileges.

My sample code for it as follows:

Code Block 
date_default_timezone_set("Europe/Madrid");
use \Firebase\JWT\JWT;
$appleCon = [
    'privateKey' => "" . file_get_contents(DIR . '/AuthKey_XXXXXXXXX.p8'),
    'apiKeyID' => 'XXXXXXXXX',
    'issuerID' => 'XXXXXXX-XXXX-XXXX-XXXX-XXXXXXXX'
];
$payload = array(
    "iss" => $appleCon['issuerID'],
    "exp" => time() + 1200,
    "aud" => "appstoreconnect-v1",
);
$jwt = JWT::encode($payload, $appleCon['privateKey'], "ES256", $appleCon['apiKeyID']);
$client = new GuzzleHttp\Client(['base_uri' => 'https://api.appstoreconnect.apple.com/v1/']);
$request = new \GuzzleHttp\Psr7\Request('GET', 'apps', [
    'headers' => [
        'Authorization' => "Bearer ".$jwt
    ]
]);
$promise = $client->sendAsync($request)->then(function ($response) {
    echo 'I completed! ' . $response->getBody();
});
try {
    $promise->wait();
}
catch (GuzzleHttp\Exception\ClientException $e) {
    $response = $e->getResponse();
    $responseBodyAsString = $response->getBody()->getContents();
    echo $responseBodyAsString;
}

I am struggling with this issue for two days, if anyone can fix or give some hints to fix this issue, will be much appreciated.

Code Block 
$response = $client->request('GET', 'apps', ['headers' => ['Authorization' => "Bearer $jwt"]])->getBody()->getContents();