Question : undeliverable email

I'm getting a bounce back email from one domain. the bounce back looks like this:

Your message did not reach some or all of the intended recipients.

      Subject:      test
      Sent:      6/9/2009 10:07 AM

The following recipient(s) cannot be reached:

      [email protected] on 6/9/2009 10:08 AM
            A critical function required for the transfer or delivery of the message was not supported by the originator of the report
            .org #5.3.3 smtp;500 5.3.3 Unrecognized command>

Would this be on my end or on the recipent? I'm running exchange server 2003 w sp2 and outlook 2007

Answer : undeliverable email

This maybe an issue with their system in that it doesn't understand the ESMTP commands

Try and change your smtp connector definition in your exchange

- Start the System Manegr
- Locate and right click the SMTP connector
- Choose properties
- In the properties go to the register Enhanced
- Activate the option "HELO instead of EHLO"

taken from http://www.winserverkb.com/Uwe/Forum.aspx/exchange-admin/24373/smtp-500-5-3-3