Postfix graylist vs Office365 servers

[farga...@gmail.com]

Hi!

My problem:
Mails sent to specific addresses are delivered very slowly, and sometimes not at all.
Office365 server(s) -> Postfix(with graylist) servers

What I managed to find out (but not 100%, that's the problem)

Recipients e-mail server type: postfix. These servers "gray list" function is used. This is due to the spam protection for the first time rejects the email, but it notes that what IP address was sent. If (after a while) a second time from the same address receives this email will be delivered. The problem: the Office365 multiple IP addresses used to send mail.

In postfix log (many times):
"....action=greylist, reason=new ...."

The problem (I think): postfix each emails handles as "first" (due to different IP addresses). And reject (gray listed), and wait for next try. Wait until the same IP address shows up again.

Ms Support answer:
"According to your issue please use this URL that is
https://technet.microsoft.com/en-us/library/dn163583(v=exchg.150).aspx
to update the EOP IP address in postfix server so that any email comes with office365 IP address it will be accepted by the postfix server."

Any Advice?
THX.