Vesta Control Panel - Forum

I realize this has been posted before but I can't find the fix
I have a fully functional subscription paid direct admin server on my network, it works fine, I'm trying to mimic the settings for Vesta, I have an external dns server and as far as I can tell everything is the same from the web portal set up, the only thing not working is sending mail, I immediately keep getting this error.
SMTP Error (550): Failed to set sender "USER" (Access denied - Invalid HELO name (See RFC2821 4.1.3)).

I have full access to the files of both servers, please guide me to the root of the problem

just found the issue, its working now

Here is the solution.

You should add smtp helo name in the configuration.

$config['smtp_helo_host'] = 'localhost';
Find the file config.inc.php from your mail client application, and add the line.

VestaCP: /etc/roundcubemail/config.inc.php