My Exchange server Public IP address is getting Blacklisted at CBL again again ( 2-3 times in last one month). It's a new server we setup 2 months ago. I found this blacklisting this morning also and get that cleared in 2 hours. But still my couple of users getting non-deliveralble from few emails receipients with error msg like below:
"ESMTP rejected your message to the following e-mail addresses:
ESMTP gave this error:
Transaction Failed Spam Message not queued.
A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk."
My questions are:
- do you think this is because of an Internal PC infection or a server configuration issue
- Should I ask my ISP change my Static IPs - do you think if that will help?
- any other suggestions? (my inbound email comes through postini just in case if you need this info)
Any help/advice will be highly appreciated.