Problem receive e-mail - 554 5.7.1

SYSTEM INFORMATION
OS type and version Ubuntu 20
Webmin version 1.9
Virtualmin version 7.1 PRO
Related packages Postfix

Fresh install, no problem to send and auto-send. Not receive. Correct DNS. Telnet and dig correct information and connected.
Thank you, waiting for suggestion.
Regards.

Hello,

Can you please contact your ISP and double check if port 25 is allowed to be used?

Virtualmin is on a VPS, and I’ve another VPS on the same server host that works with postfix. How can I configure Virtualmin mail on a different port?
Thank you.
Regards.

I assume both VPS’s have different IP addresses - if so Postfix should be fine on both (using the same port\s).

We need to see the relevant mail log entries. The client does not have useful information about why it failed.