Helo command rejected: Host not found

I can't send email to a particular company. I have verified the email addresses of the two recipients. Here is the NDR I get.

Final-Recipient: rfc822;joanna_medina@biometmail.com
Action: delayed
Status: 4.0.0
Diagnostic-Code: smtp;450 <POSTMAN.VALUEPLASTICS>: Helo command rejected: Host not found
Will-Retry-Until: Wed, 13 Apr 2005 14:08:56 -0600
X-Display-Name: 'joanna_medina@biometmail.com'

Final-Recipient: rfc822;dorothy_casas@biometmail.com
Action: delayed
Status: 4.0.0
Diagnostic-Code: smtp;450 <POSTMAN.VALUEPLASTICS>: Helo command rejected: Host not found
Will-Retry-Until: Wed, 13 Apr 2005 14:08:56 -0600
X-Display-Name: 'dorothy_casas@biometmail.com'

Any idea why? Thanks!
JohnValueAsked:
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SembeeConnect With a Mentor Commented:
http://www.dnsreport.com/tools/dnsreport.ch?domain=biometmail.com

Well "biometmail.com" has no reverse DNS. It also looks like they have a PIX firewall which might be causing problems.

However the problem might be at your end. If you don't have reverse DNS or your machine is announcing an invalid domain name then the remote end may have some spam traps that don't allow your server to deliver the email.

Simon.
Exchange MVP.

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