Error joining discord server

[remsooo]

Hey, can anyone help? I keep crashing the same error and I don't know what it's caused by

<?php

  require __DIR__ . '/vendor/autoload.php';

  use Wohali\OAuth2\Client\Provider\Discord;
  use RestCord\DiscordClient;

  session_start();

  $provider = new \Wohali\OAuth2\Client\Provider\Discord([
      'clientId' => 'xyz',
      'clientSecret' => 'xyz',
      'redirectUri' => 'xyz'
  ]);

  if (!isset($_GET['code'])) {

      $options = [
          'scope' => ['guilds.join']
      ];
      $authUrl = $provider->getAuthorizationUrl($options);
      $_SESSION['oauth2state'] = $provider->getState();
      header('Location: ' . $authUrl);

  } elseif (empty($_GET['state']) || ($_GET['state'] !== $_SESSION['oauth2state'])) {

      unset($_SESSION['oauth2state']);
      exit('Invalid state');

  } else {

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

    try {

      $user = $provider->getResourceOwner($token);
      $discord_id = $user->getId();
      $args = [
        'guild.id' => xyz,
        'user.id' => intval($discord_id),
        'access_token' => $token
      ];

      $client = new DiscordClient([
        'token' => 'xyz'
      ]);

      var_dump($client->guild->addGuildMember($args));

    } catch (Exception $e) {
      exit("Oh dear... $e");
    }
  }

?>

and Error code

Oh dear... Wohali\OAuth2\Client\Provider\Exception\DiscordIdentityProviderException: 401: Unauthorized in /var/www/html/discord/vendor/wohali/oauth2-discord-new/src/Provider/Exception/DiscordIdentityProviderException.php:47 Stack trace: #0 /var/www/html/discord/vendor/wohali/oauth2-discord-new/src/Provider/Exception/DiscordIdentityProviderException.php(33): Wohali\OAuth2\Client\Provider\Exception\DiscordIdentityProviderException::fromResponse() #1 /var/www/html/discord/vendor/wohali/oauth2-discord-new/src/Provider/Discord.php(110): Wohali\OAuth2\Client\Provider\Exception\DiscordIdentityProviderException::clientException() #2 /var/www/html/discord/vendor/league/oauth2-client/src/Provider/AbstractProvider.php(628): Wohali\OAuth2\Client\Provider\Discord->checkResponse() #3 /var/www/html/discord/vendor/league/oauth2-client/src/Provider/AbstractProvider.php(784): League\OAuth2\Client\Provider\AbstractProvider->getParsedResponse() #4 /var/www/html/discord/vendor/league/oauth2-client/src/Provider/AbstractProvider.php(767): League\OAuth2\Client\Provider\AbstractProvider->fetchResourceOwnerDetails() #5 /var/www/html/discord/discord.php(38): League\OAuth2\Client\Provider\AbstractProvider->getResourceOwner() #6 {main}