Symfony_mailer error

Symfony_mailer does not work on Drupal 10 erroring out with:

Connection to "process /usr/sbin/sendmail -bs" has been closed unexpectedly

The sendmail command it’s a wrapper of ssmtp (a command line tool that is used to send email over secure smtp server). ssmtp command does not support the -bs option.

There is a workaround to modify Drupal module and add the following in the settings.php and symfony_mailer.mailer_transport.sendmail.yml

This might be useful to other customers as well so feel free to share.

settings.php:

$settings['mailer_sendmail_commands'] = [
  ini_get('sendmail_path')
];

symfony_mailer.mailer_transport.sendmail.yml:

configuration:
  query:
    command: '/usr/sbin/sendmail -t -i'
];

Please note this is just a workaround and it's not something we will be able to provide assistance in details.

If you have further questions regarding this topic contact support.