Thank you for your commitment.
I solved the problem. It is not PMG's fault, but Zimbra
It turned out that Zimbra rejected these messages.
For people who will encounter a similar problem:
thanks to the post:
https://forums.zimbra.org/viewtopic.php?f=15&t=63627
I found out that
This is nearly...
PMG log after sending the message
As you can see in the screenshot attached, the message has reached PMG
Feb 28 13:43:23 poczta postfix/postscreen[1149]: CONNECT from [193.30.160.48]:30254 to [192.168.27.10]:25
Feb 28 13:43:23 poczta postfix/postscreen[1149]: PASS OLD [193.30.160.48]:30254...
Hello. At first, I apologize for my English. I am supporting the google translator.
I have a problem.
After setting up the DNS server on the external hosting, I installed PMG. Behind him is the Zimbra server.
The current situation is that e-mails reach the PMG but are not forwarded to Zimbra...