Good Morning,
We have changed our external IP Address of our mail server earlier this week and ever since we are getting bounce backs from email addresses we can normally send to.
One of the error messages we have been receiving:
Reason: 571 Delivery not authorized, message refused
The message subject was: Test Email Message
The message date was: Fri, 7 Aug 2015 08:48:52 +0100
The message identifier was: C8/BC-15765-5E264C55
The message reference was: server-8.tower-27.messagelabs.com!1438933732!38738847!1
Please do not reply to this email as it is sent from an unattended mailbox.
Please visit www.messagelabs.com/support for more details
about this error message and instructions to resolve this issue.
Does any one have any suggestions on how to fix this? Or explained why this is happening?
I have done the following:
Updated the external DNS record for the mail server.
Informed the ISP that the IP is going to be used for the email server and sent them the domain name to update the records at their end.
Added the external IP address into the relay connector.
Checked the IP address isn't blacklisted.