Emails bouncing back

I recently uninstalled McAfee and replaced with the trial verions of NOD32 2.7 on my wife's computer. She runs a home business and often sends out mass emails. The first time she tried after NOD was installed, they ALL came back as undeliverable. She tried sending them out in smaller groups and they went through. Previous to installing NOD, she sent out many mass emails and did not have them bounce back.

The emails all had a message about (paraphrasing) the recipient ISP being down. The emails came back in groups sorted by ISP. So one email said all the @yahoo.com ISP was down; the next email said all the @gmail.com ISP were down, etc.

Can anyone tell me if this could be related to NOD32? Is there a setting that I can adjust to allow mass emails to be sent out?

Thanks.

 

Hi ! No , this should not be related to NOD32 . NOD32 doesn't scan outgoing emails except those in Office Outlook . Even in that case this have never happened (at least to me) . I am 99% sure the problem is somewhere else

 

Might it be that the ISP has recently introduced a spam filter limiting the number of emails transmitted en masse?.

 

I haven't had ZoneAlarm Pro in years, but they have/had a email filter that limited the number of emails that you could send out or receive in so many seconds.

 

Thanks, I wasn't sure if it was NOD32. The timing just made me suspicious. Here is a copy of the relevant portions of the returned email:

This Message was undeliverable due to the following reason:

Your message was not delivered because the Domain Name System
(DNS) for the destination computer is not configured correctly.
The following is a list of reasons why this error message could
have been generated. If you do not understand the explanations
listed here, please contact your system administrator for help.

- The host does not have any mail exchanger (MX) or
address (A) records in the DNS.

- The host has valid MX records, but none of the mail
exchangers listed have valid A records.

- There was a transient error with the DNS that caused
one of the above to appear to be true.

You may want to try sending your message again to see if the
problem was only temporary.

DNS for host aol.com is mis-configured.

The following recipients did not receive this message:

<xxxxxxxx@aol.com>

Please reply to <Postmaster@charter.net>
if you feel this message to be in error.

When she sent out the mass email, she got a separate "returned email" for each DNS. So if her mass email included addresses to eight specific DNS's, she got eight returned emails.

You're probably right and it has nothing to do with NOD32. I'll come back to this thread if I have further problems/insights.

Thx.