Send mail over smtp -Error 500 5.3.3

ℹ️ Support
2

i think i have a problem similar to this thread:

but i do not know where i should place the lines:

$transport = Swift_SmtpTransport::newInstance(‘[fqdn.mailserver.com](http://fqdn.mailserver.com)’, 587, ‘tls’)
->setUsername(‘user’)
->setPassword(‘Password’)
->setStreamOptions(array(‘ssl’ => array(‘allow_self_signed’ => true, ‘verify_peer’ => false)));

tried to add:

"mail_smtpstreamoptions" => array(
'ssl' => array(
    'allow_self_signed' => true,
    'verify_peer' => false,
    'verify_peer_name' => false
  )
),

in my config file but nothing changed…