Out: 220 mta1.mydomain.com ESMTP 

 In:  EHLO XRX_0000AA71FBF4.otherdomain.ca
 Out: 250-mta1.mydomain.com
 Out: 250-PIPELINING
 Out: 250-SIZE 20480000
 Out: 250-ETRN
 Out: 250-STARTTLS
 Out: 250-AUTH LOGIN PLAIN
 Out: 250-AUTH=LOGIN PLAIN
 Out: 250-ENHANCEDSTATUSCODES
 Out: 250-8BITMIME
 Out: 250 DSN
 In:  MAIL FROM: <outbound@otherdomain.ca>
 Out: 250 2.1.0 Ok
 In:  RCPT TO: <user@otherdomain.ca> ORCPT=rfc822;user@otherdomain.ca
 Out: 451 4.3.5 Server configuration error

Session aborted, reason: lost connection