I'm not sure how to solve this one and even not sure if it's a drupal issue or misconfiguration.
I'm running a Drupal site (7.22) and have huge problems with the sending mails. Most of the mails can't be delivered and I (the admin) get immediately a Mail Delivery System message:
This is the mail system at host OUR_MAIL_HOST.
I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can delete your own text from the attached returned message.
The mail system
USER_MAIL_HOST said: 450 4.7.1
: Client host rejected: Policy Rejection- Greylisting in action; Please try again later. (in reply to RCPT TO command) Reporting-MTA: dns; OUR_MAIL_HOST X-Postfix-Queue-ID: D8047189CE9 X-Postfix-Sender: rfc822; admin@mail Arrival-Date: Wed, 26 Feb 2014 08:22:24 +0100 (CET)
Final-Recipient: rfc822; user@mail Action: failed Status: 4.7.1 Remote-MTA: dns; USER_MAIL_HOST Diagnostic-Code: smtp; 450 4.7.1 < OUR_MAIL_HOST[OUR_MAIL_HOST_IP]>: Client host rejected: Policy Rejection- Greylisting in action; Please try again later.
The original mail content...
So to get a mail through this greylisting-filter requires sending the mail again, but I don't know whether it should be done via Drupal or via the mail server? The admins of the mail server told me to send the mail again, but this means, I have to tell Drupal to send each mail twice if it gets greylisted. This sounds pretty odd to me and I'm sure there is a clean solution. So any ideas? I'm sure I'm not the only one with such a problem.