I need someone to check our dns-postfix configuration as there are some servers that reject receiving or sending email to our server.
Our www is at a hosting site and we redirected the MX records to a local server.
Most of our email works fine, only some corporate, very picky servers are rejecting, some won't tell a thing, some send the following message
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
<email@example.com>: host [url removed, login to view][x.x.x.x] said: 550-Verification failed for
<firstname.lastname@example.org> 550-The mail server could not deliver mail to
email@example.com. The account or domain may not exist, they may be
blacklisted, or missing the proper dns entries. 550 Sender verify failed
(in reply to RCPT TO command)