I run exchange 2013 and am receiving the following error when our users send emails to a certain domain. This issue just started a few hours ago:
This is the Postfix program at host example.xyz.ac.xx.
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 Postfix program
<email@example.com>: host 1xx.1xx.x.1x[1xx.1xx.x.1x] said: 550 5.7.1 Message
rejected due to content restrictions (in reply to end of DATA command)
Need any assistance n resolving this issue.