Email issue error 550 domain does not exist

Hello ,

im running a sbs 2011 with exchange 2010 , this mail server has about 4 email domains running and i added 1 more the same way i do everything.

the MX points to a Barracuda 300  spam firewall  then from the Cudda to the external IP of the mail server. same way the other 4 are setup.  this domain can send internally fine and send out but when you try to send to it you get  

Requested gave this error:
No such domain at this location

A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk.

Diagnostic information for administrators:

Generating server:mailserver.local

cscally@emailaddress.com
Requested #550 No such domain at this location ##

BUT   when i do an smtp test with the MX it works fine

Testing SMTP connection for receivingdomain.com with the following parameters:

 SMTP Server         SMTP Port         Use MX Records
 xxx.xxx.xxx.xxx         25           Yes


Test results:
Successfully sent test message:
Connected to xxx.xxx.xxx.xxx:25 session output follows:
220 receivingserver Microsoft ESMTP MAIL Service ready at Fri, 2 Dec 2011 13:24:12 -0500
EHLO barracuda.sendingdomain.com
250-receivingserver Hello [xxx.xxx.xxx.xxx]
250-SIZE 10485760
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-X-ANONYMOUSTLS
250-AUTH NTLM
250-X-EXPS GSSAPI NTLM
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250-XEXCH50
250-XRDST
250 XSHADOW
mail from:<smtptest@barracudanetworks.com>
250 2.1.0 Sender OK
rcpt to:<cscally@emailaddress.com>
250 2.1.5 Recipient OK
data
354 Start mail input; end with <CRLF>.<CRLF>
Content-type: text/plain; charset=utf-8
From: <smtptest@barracudanetworks.com>
Date: Fri Dec 2 13:24:13 2011
Subject: Test message

This is a test message from your Barracuda Spam & Virus Firewall.
.


and even from other verify email address sites it works fine