Unable to mail from Joomla on Debian 7 / Virtualmin

I have recently moved from an old debian 6 server to a brand new Debian 7 server running Virtualmin.

Everything seems ok except mailing.

All my mail for myself and peoples domains that I host is dealt with by third party mailers (godaddy, gmail) and I have MX records pointing accordingly. But I have noticed that when I mail ‘virtual server’ owners, the mail goes to an inbox on virtualmin.

Even though I dont want to recieve, I still need to send mail from the virtualmin server, usually from websites… i.,e Joomla when a user signs up.

Every ISP, or server I have done in the past this function just works on any new install. Joomla can use SENDMAIL, PHPMAIL or SMTP. I generally dont have to configure any SMTP

None of these functions work. Mail just does not leave. The websites does’nt error, but when I look at the mail error logs there are no errors at all I can work with.

Please can anyone who runs a CMS such as Joomla advise how I can achieve this. Many thanks

I have managed to get around the problem using SMTP and a relay account, but I would still like to get my head around why SENDMAIL and PHPMail is not working