"419 Page Expired" error when sending request to another instance of Laravel using guzzle

Hi,

I have been struggling with this problem for two days. I wanna hit my head against the wall.

I have an API built with Lumen, and a web-client for the application built with Laravel. the web-client uses guzzle to send requests to the API (Lumen).

on the local environment, everything is ok. when I uploaded the Laravel and Lumen on Host, the problem arose out of nowhere.

THE PROBLEM:

when the web-client (Laravel) sends a request to Lumen, a "419 Page Expired" page turns back as result. BUT when I use CURL to send a request to Lumen, it turns back a successful response.

Guzzle:

private const BASE_URI = 'http://example.com/api';

public static function sendRequest($method, $uri = '', array $options = [])
{
    $client = new Client([
        'base_uri' => self::BASE_URI,
        'headers' => [
            'Authorization' => "Bearer {session('api_token')}",
        ]
    ]);

    try {
        $response = $client->request($method, $uri, $options);
    } catch (RequestException $exception) {
        $response = $exception->getResponse();
    }

    $responseContent = $response->getBody()->getContents();

    dd($responseContent);

    $result = json_decode($responseContent);

    return self::check($result);
}

CURL:

protected static function sendPost($phoneNumber, $password)
{
    $url = self::BASE_URI . '/login';

    $fields = array
                (
                    'phone_number' => $phoneNumber,
                    'password' => $password
                );
                
    $handler = curl_init($url);             
    curl_setopt($handler, CURLOPT_CUSTOMREQUEST, "POST");
    curl_setopt($handler, CURLOPT_POSTFIELDS, $fields);                       
    curl_setopt($handler, CURLOPT_RETURNTRANSFER, true);
    $responseContent = curl_exec($handler);

    dd($responseContent);
    
    $result = json_decode($responseContent);

    return self::check($result);
}

a portion of the response:

    <title>Page Expired</title>

    <!-- Fonts -->
    <link rel="dns-prefetch" href="//fonts.gstatic.com">
    <link href="https://fonts.googleapis.com/css?family=Nunito" rel="stylesheet">

    <!-- Styles -->
    <style>
        html, body {
            background-color: #fff;
            color: #636b6f;
            font-family: 'Nunito', sans-serif;
            font-weight: 100;
            height: 100vh;
            margin: 0;
        }

        .full-height {
            height: 100vh;
        }

        .flex-center {
            align-items: center;
            display: flex;
            justify-content: center;
        }