@Dariuso I tried your server settings in my phplist. When I sent a test message I got a clear explanation of the problem, regarding the hosts certificate not matching.
This output appears at the top of the page after you send a test message.
You might be able to work around the problem by not validating the certificate. Try adding this to the end of your config.php file
$phpmailer_smtpoptions = array (
'ssl' => array(
'verify_peer' => false,
'verify_peer_name' => false,
'allow_self_signed' => true
)
);