Question : New users can't recieve email from outside the organisation. Exchange 2007.

We have a situation where new mail users can be created within Exchange but cannot receive messages sent to them from outside the organisation. These same addresses work fine internally and can send email to the outside without any problems.

The issue also applies to mail aliases placed on users who have working exchange accounts. Messages sent to their alias from outside the organisation bounce back

External senders receive a similar error to the one below when sending too the new users/aliases:

Delivery to the following recipient failed permanently:

    [email protected]

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 Previous (cached) callout verification failure (state 14).

Running a verification test on network-tools.com produces the following:

[Contacting mail.problemdomain.com [123.456.789.123]...]
[Connected]
220 mail.problemdomain.com incoming mail service ESMTP Wed, 25 Aug 2010 11:20:48 +1200
EHLO Network-Tools.com
250-mail.problemdomain.com Hello gateway2.network-tools.com [67.222.132.194]
250-SIZE 52428800
250-PIPELINING
250 HELP
VRFY new.user
252 Administrative prohibition
RSET
250 Reset OK
EXPN new.user
550 Administrative prohibition
RSET
250 Reset OK
MAIL FROM:<admin@Network-Tools.com>
250 OK
RCPT TO:<new.user@problemdomain.com>
550-Callout verification failed:
550 550 Unrouteable address
[Address has been rejected]
RSET
250 Reset OK
QUIT
221 MAIL.problemdomain.com closing connection
[Connection closed]

Additional information - I personally don't know when this began or how long this may have been happening for as I've just taken over on this. I suspect it has something to do with the recipient update policy, however the account in question, I understand, has been around for two weeks already.

Answer : New users can't recieve email from outside the organisation. Exchange 2007.

Do yo have a 3rd party receiving your emails before they pass them on to you or do you receive them directly?

Do you have a device such as a Barracuda appliance before your Exchage Server?

If yes - then the device / 3rd party needs to be updated with the new email address.

If no - I'll think up plan B!