HELP! Urgent - no activation email sent from Virtuemart

[nicole2292]

It is a legal requirement of our store that an activation email is sent. We must use this feature.

If a user is registered from Joomla then the email is received. If a user is registered from Virtuemart it says
"Registration Completed!

Your account has been created and an activation link has been sent to the e-mail address you entered. Note that you must activate the account by clicking on the activation link when you get the e-mail before you can login."

However no email is ever received. As I mentioned this is not a problem with the server sending emails as one is sent just fine from the Joomla registration.

This is SUPER MEGA URGENT! Store is supposed to be going live tomorrow!

We are on Joomla 2.5.6 and Vituemart 2.0.8e.

Please help asap.

[nicole2292]

Ok this is quite a strange problem.

I'm actually getting failed mail for both the admin notification and the activation email (both were sent to email addresses on the same server).

Turns out it only occurs to some email addresses (those with the same web host) - although a completely different server. Unfortunately they are one of the largest hosts in Australia so lots of people use them...

What is really strange is that it only happens from the virtuemart registration. Does virtuemart not put in the from email address correctly or some other item in the headers is done differently to when the joomla registration sends an email?

Can someone please assist me with how virtuemart does this differently to a straight joomla registration so I can fix the problem?

Edited failed mail message below:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

  name@domain.com
    SMTP error from remote mail server after RCPT TO:<name@domain.com>:
    host removed for security [removed for security]:
    550-Verification failed for <removed for security>
    550-The mail server could not deliver mail to removed for security.  The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.
    550 Sender verify failed

------ This is a copy of the message, including all the headers. ------

Return-path: <removed for security>
Received: from removed for security with local (Exim 4.77)
        (envelope-from <removed for security>)
        id 1SvnvC-00376P-TH
        for name@domain.com; Mon, 30 Jul 2012 19:13:58 +0800
To: name@domain.com
Subject: A new shopper test47 registered  at your shop removed for privacy
Date: Mon, 30 Jul 2012 19:13:58 +0800
From: removed for security <removed for security>
Message-ID: <removed for security>
X-Priority: 3
X-Mailer: PHPMailer 5.2.1 (http://code.google.com/a/apache-extras.org/p/phpmailer/)
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/html; charset="utf-8"

Any ideas?