Invalid_grant after page reload Twinfield

I am currently trying to setup the Twinfield API. I believe I am almost there, almost... I managed to retrieve an accessToken and a refreshToken, but somehow this works only on the first page load. After reloading the page I get the 'invalid_grant' error. I am not exactly sure what goes wrong, because it actually is working on the first page load.

Here is my code:

        $provider    = new OAuthProvider([
        'clientId'     => 'clientId',
        'clientSecret' => 'clientSecret',
        'redirectUri'  => 'http://127.0.0.1:8000'
    ]);

    if (!isset($_GET['code'])) {
        $options = [
            'scope' => ['twf.user', 'twf.organisation', 'twf.organisationUser', 'offline_access', 'openid']
        ];
        $authorizationUrl = $provider->getAuthorizationUrl($options);
        $_SESSION['oauth2state'] = $provider->getState();
        header('Location: ' . $authorizationUrl);
        exit;
    } elseif (empty($_GET['state']) || (isset($_SESSION['oauth2state']) && $_GET['state'] !== $_SESSION['oauth2state'])) {
        if (isset($_SESSION['oauth2state'])) {
            unset($_SESSION['oauth2state']);
        }
        exit('Invalid state');
    } else {
        try {

            $accessToken = $provider->getAccessToken('authorization_code', [
                'code' => $_GET['code']
            ]);
            
            $refreshToken = $accessToken->getRefreshToken();

            echo 'Access Token: ' . $accessToken->getToken() . "<br>";
            echo 'Refresh Token: ' . $accessToken->getRefreshToken() . "<br>";
            echo 'Expired in: ' . $accessToken->getExpires() . "<br>";
            echo 'Already expired? ' . ($accessToken->hasExpired() ? 'expired' : 'not expired') . "<br>";

            $office       = \PhpTwinfield\Office::fromCode("someOfficeCode");
            $connection  = new \PhpTwinfield\Secure\OpenIdConnectAuthentication($provider, $refreshToken, $office);

           // $offices = $officeApiConnector->listAllWithoutOfficeCode();

        } catch (\League\OAuth2\Client\Provider\Exception\IdentityProviderException $e) {
            // Failed to get the access token or user details.
            exit($e->getMessage() . ' error');
        }

I hope someone can tell me more about what I have been doing wrong. Thanks for the help already.

I used a session counter to make sure a new authorization code is requested every time the page gets refreshed. This way the authorization code always matches the access token and refresh Token.

<?php


namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use PhpTwinfield\ApiConnectors\CustomerApiConnector;
use PhpTwinfield\Secure\Provider\OAuthProvider;
use PhpTwinfield\Secure\OpenIdConnectAuthentication;


  class TWFconnector
  {
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle(Request $request, Closure $next)
    {
        session_start();
        if (!isset($_SESSION['arr']['counter'])) {
            $_SESSION['arr']['counter'] = 0;
        } else {
            $_SESSION['arr']['counter']++;
        }

    $twin_client_id = '';
    $twin_client_secret = '';
    $twin_client_uri = '';

    $provider    = new OAuthProvider([
        'clientId'     => $twin_client_id,
        'clientSecret' => $twin_client_secret,
        'redirectUri'  => $twin_client_uri,
    ]);

    if (!isset($_GET['code'])) {
        $options = [
            'scope' => ['twf.user', 'twf.organisation', 
    'twf.organisationUser', 'offline_access', 'openid']
        ];

        $authorizationUrl = $provider->getAuthorizationUrl($options);

        header('Location: ' . $authorizationUrl);
        $_SESSION['arr']['counter'] = 0;
    } elseif($_SESSION['arr']['counter'] > 1) {
        header('Location: http://127.0.0.1:8000/');
    } else {
        $accessToken = $provider->getAccessToken('authorization_code', [
            'code' => $_GET['code']
        ]);

        $refreshToken = $accessToken->getRefreshToken();

        $office       = \PhpTwinfield\Office::fromCode("");
        $connection = new OpenIdConnectAuthentication($provider, 
        $refreshToken, $office);

            print_r($connection);
        }
        return $next($request);
    }
}