it says that " The IP of one or more of your mail server(s) have no reverse DNS (PTR) entries "
i write the support team that i want to setup reverse DNS and they said to me,
The Reverse DNS is on the server, we can not put this on your IPs as they are not the master IPs, this is normal, and there is a reverse DNS, just not for your nameservers. If you can not send mail, its because they are blocking you.
Some email servers require that both FORWARD and REVERSE records to a mail server match.
I'm not sure if that's the problem in this case, but i know for sure this is a configurable option in postfix.
the only way to be able to send mail to those people who block it... is to have them whitelist you or get your ISP or whoever is giving you the IP addresses to reverse them for you... or to allow you to reverse them yourself.
another option is to seperate your mail server from your nameservers... and reverse that IP (or have your isp do it)... as it sounds like they aren't going to reverse the ips of your nameservers.
if you google "smtp reverse dns" there's alot of reading on this subject..