550 Error Unroutable Address

I have been able to find lots of information on 550 errors, but not so much on unrouteable addresses.

When I try to send email to clrockwell [;at'] truckingshow ['dot'] com it responds back with:

Code:
clrockwell [;at'] truckingshow ['dot'] com : host truckingshow.com[209.40.205.67] said: 550 Unrouteable address (in reply to RCPT TO command)
The email addresses were added through cpanel, ls -l shows them all there. We have moved servers and, as best I could, I compared everything and it seems to be the same but obviously I'm missing something.

Edit: Also, when I visit truckingshow.com/webmail I am prompted for username and password. I enter it in (email address above and password) and then it takes me to the normal cpanel webmail page giving me the option to choose horde, squirrel or roundcube. I select one, then the software itself (not the .htaccess) asks for my login again, then denies it. I have reset these passwords to the same exact thing over and over, so I know for sure the username and password are correct.

Edit 2: from network tools

Code:
Contacting truckingshow.com [209.40.205.67]...]
[Connected]
220-truckingshow.com ESMTP Exim 4.69 #1 Fri, 11 Jul 2008 10:39:10 -0700
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.
EHLO Network-Tools.com
250-truckingshow.com Hello Network-Tools.com [67.222.132.194]
250-SIZE 52428800
250-PIPELINING
250-AUTH PLAIN LOGIN
250-STARTTLS
250 HELP
VRFY clrockwell
252 Administrative prohibition
RSET
250 Reset OK
EXPN clrockwell
550 Administrative prohibition
RSET
250 Reset OK
MAIL FROM:<admin@Network-Tools.com>
250 OK
RCPT TO:<clrockwell@truckingshow.com>
550 Unrouteable address
[Address has been rejected]
RSET
250 Reset OK
QUIT
221 truckingshow.com closing connection
[Connection closed]