PHPmailer SMTP SSL error

[sanderbee]

We use PHPMailer 5.2.21. Our server is configured to use the local SMTP. So, the general PHPMailer commando looks like this:

$mail = new PHPMailer();
$mail->From = '[email protected]';
$mail->Host = 'localhost';
$mail->IsSMTP();
...

Since PHP5.6, this doesn't work anymore, because the certificate does not match. We get the following error:

Warning: stream_socket_enable_crypto(): Peer certificate CN='*.thisvps.com' did not match expected CN='localhost' in /ho...PHPMailer_latest/class.smtp.php

(*.thisvps.com is a valid, not-selfsigned wildsign certificate that is installed for the SMTP server, before this certificate was installed, it doesn't work eighter (no certificate error).).

I can suppress this error using:

$this->smtpConnect([
   'ssl' => [
       'verify_peer' => false,
       'verify_peer_name' => false,
       'allow_self_signed' => true
   ]
]);

But, is that the correct way to go? I'm not a big fan of suppressing errors;). Or maybe there is an error in our configuration? Or why is the SMTP request to 'localhost' checked at all?

Version info: PHP 5.6.30, PHPMailer: 5.2.21

Any suggestion are welcome, thanks in advance!