Error sending email: Connection to "process /usr/sbin/sendmail -bs" has been closed unexpectedly

As mentionned in this issue " https://www.drupal.org/project/symfony_mailer/issues/3487054 🐛 Connection to "process /usr/sbin/sendmail -bs" has been closed unexpectedly. Active ", I get this error on each task CRON. I don't see which service/element generate this error.

Do I use this solution, https://www.drupal.org/project/symfony_mailer/issues/3487054#comment-158... 🐛 Connection to "process /usr/sbin/sendmail -bs" has been closed unexpectedly. Active , or block all sending during CRON jobs?

Thanks.