We send mail business failed, the email is returned to the sender with the following content errors.
"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 mail system
<firstname.lastname@example.org>: lost connection with 127.0.0.1[127.0.0.1] while
sending end of data -- message may be sent more than once"
if I turn off antivirus and antispam mail send mail well, but we receive many spam mail.