roundcube SMTP Error (220): Authentication failed.

I cannot send an email, the mail server works but not Roundcube... What is the correct setup?
this is what I have:

Code:

$config['default_host'] = 'tls://server2.revelhost.net';

  // SMTP server host (for sending mails).
  // Enter hostname with prefix ssl:// to use Implicit TLS, or use
  // prefix tls:// to use STARTTLS.
  // Supported replacement variables:
  // %h - user's IMAP hostname
  // %n - hostname ($_SERVER['SERVER_NAME'])
  // %t - hostname without the first part
  // %d - domain (http hostname $_SERVER['HTTP_HOST'] without the first part)
  // %z - IMAP domain (IMAP hostname without the first part)
  // For example %n = mail.domain.tld, %t = domain.tld
  // To specify different SMTP servers for different IMAP hosts provide an array
  // of IMAP host (no prefix or port) and SMTP server e.g. ['imap.example.com' => 'smtp.example.net']


$config['smtp_server'] = 'tls://server2.revelhost.net';


// SMTP port. Use 25 for cleartext, 465 for Implicit TLS, or 587 for STARTTLS (default)
$config['smtp_port'] = 587;

// SMTP username (if required) if you use %u as the username Roundcube
// will use the current username for login
$config['smtp_user'] = '%u';

// SMTP password (if required) if you use %p as the password Roundcube
// will use the current user's password for login
$config['smtp_pass'] = '%p';


$config['smtp_conn_options'] = [
  'ssl' => [
    'peer_name' => ' %n',
    'cafile' => '/home/revelhost/domains/mailbox.revelhost.net/ssl.cert',
  ],
];