Hi All.
I wonder if anyone could assist with some advice. I have really tried everything and don't seem to be having any luck.
Recently emails to one of our main clients started being rejected. It just happened all of a sudden.
We have been sending to them for years with no issues. I might add that I can send to them from a test Exchange server at my house, as well as my personal Gmail account. I have checked my domain and its not blacklisted. We are sending our email out via a smarthost.
Please note I have removed any disclaimers as well as signatures. This is a plain email containing only text.
This is the message I get when sending email to this specific organisation:
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:
SMTP error from remote mail server after end of data:
xxxx.xxxxxx.gov.za [41.x.x.x]:
550 5.7.1 Message rejected due to content restrictions.
There is actually another company too. This is the message we get from them:
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:
SMTP error from remote mail server after end of data:
host xxxx.mimecast.co.za [xx.xx.xxx.xx]: 554 Email rejected due to security policies -http://www.mimecast.com/knowledgebase/KBID10473.htm#554
We are using exchange 2003 sp2
Any thoughts would be appreciated.
Regards,
Shaun