My Virtualmin default configuration (the one created by the script) could send emails between users on the same domain. E.g. firstname.lastname@example.org < — > email@example.com. But when I would like to send an email from firstname.lastname@example.org to an external address like email@example.com I get the following error message:
“'Server error: '554 5.7.1 firstname.lastname@example.org: Relay access denied”
It could be related to Postfix, Spamassassin (NS are not registered with a domain registrar yet) or Port 25 blocked on OpenVZ.
Port 25 is not blocked on OpenVZ machine because I can use Outlook externally. I created 2 email address on mytestdomain.com and I a sending emails between these accounts. Emails are sent and received immediately without errors.
Port 25 is not blocked on VPS. See above. I can use telnet without problems.
Spamassassin couldn’t be a problem in my opinion. If I can send email from user1 to user2 I can send user1 to other email address.
It could be Postfix with Relay. Any advices?