Error: 'Server error: '554 5.7.1 <>: Relay access denied

My Virtualmin default configuration (the one created by the script) could send emails between users on the same domain. E.g. < — > But when I would like to send an email from to an external address like I get the following error message:

“'Server error: '554 5.7.1 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 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?

Thank you.


The “Relay Access Denied” error usually means that someone attempted to send an email using a client such as Outlook or Thunderbird, but did so without setting it to authenticate while sending the email.

Could that be the case here?


I reinstalled Virtualmin and I don’t get this message anymore. Pretty strange. I will revise some tutorial about Postfix/Dovecot to understand better the configuration.

Many thanks for your help.