We have a customer that is not able to send e-mail to users from our organization. The e-mails are bouncing back with:
"554 Your access to this mail system has been rejected due to the sending MTA's poor reputation. If you believe that this failure is in error, please contact the intended recipient via alternate means."
I am trying to whitelist this sender and so far nothing works.
Any help would be appreciated.
Once you have the IP, check your HAT under Mail Policy/HAT overview...
Make sure to select the inbound listener, then check open the appropriate sender group and add the IP.
Now whatever Mail flow policy is assigned to that policy will apply to mail from that address. Make sure its doing what you want it to.
IPs are matched to Sender group from the TOP down, just like mail policy, so this IP needs to go into sender group that is above the groups based on SBRS score (Blocked, suspect, unknown in this example).
Thank you for replying. I've looked up the MX records IP addresses of the sender in scope. The domain name, along with IP addresses were added to the allow list.
I've noticed that when running an e-mail trace report, there are no results returned, even when using a very broad search criteria for this sender. This is not helping, as I don't have any specific details I can work with.
- Rejected Connection Handling was already enabled
- "BLOCKED" mail flow policy was already set for "REJECT"
I've asked the sender to reply to test e-mails and ther e-mail trace reports are showing zero results, it looks that the e-mails are not evern reaching the ESAs.
I was provided a bounced e-mail header and I can see the our ESA IP address as it rejected the message:
Reason: There was an error while attempting to deliver your message with [Subject: <removed>] to <firstname.lastname@example.org>. MTA <server name> received this response from the destination host IP - <ESA IP address> - 554 , 554-<ESA FQDN>
554 Your access to this mail system has been rejected due to the sending MTA's poor reputation. If you believe that this failure is in error, please contact the intended recipient via alternate means.