I check my email in the website: https://www.mail-tester.com . it works perfectly
i have only one problem. emails are return mail delivery system mailer-daemon. i don’t know where is the problem you see the image
the same problem happened in gmail i send an test email from gmail the error return like in the image
by the way i activated spamassasin and MailScanner.
please is there anyone have the same error and what is the solution? and how can i solve this problem?