Disable entcryption for SMTP server

oooo-ps

My local network does not use it, how can I disable?
Documentation say that I can't there is ssl or tls options only:
https://docs.flarum.org/2.x/mail#smtp

KBExit

oooo-ps just leave the field blank.

oooo-ps

thanks, but I'm not sure the blank option changes these options:
https://symfony.com/doc/current/mailer.html#disabling-automatic-tls

// vendor/flarum/core/src/Mail/SmtpDriver.php

    public function buildTransport(SettingsRepositoryInterface $settings): TransportInterface
    {
        return $this->factory->create(new Dsn(
            $settings->get('mail_encryption') === 'tls' ? 'smtps' : 'smtp',
            $settings->get('mail_host'),
            $settings->get('mail_username'),
            $settings->get('mail_password'),
            $settings->get('mail_port'),
            [['auto_tls'=>false],['require_tls'=>false]] // not sure yet I really want these options defined (from $settings)
        ));
    }

then I see

// vendor/symfony/mailer/Transport/Smtp/EsmtpTransportFactory.php
$autoTls = '' === $dsn->getOption('auto_tls') || filter_var($dsn->getOption('auto_tls', true), \FILTER_VALIDATE_BOOL);
$tls = 'smtps' === $dsn->getScheme() ? true : ($autoTls ? null : false);
//..
$transport->setRequireTls($dsn->getBooleanOption('require_tls'));