We are migrating internally from Exchange 2003 to 2010. I have moved a couple test mailboxes and am able to send email from the mailboxes on 2010 to the 2003 server, but mailboxes on the 2003 server cannot email to the mailboxes on 2010. I get this bounce back:
The following recipient(s) cannot be reached:
Test1 on 2/15/2011 8:48 AM
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
#5.5.0 smtp;550 sorry, no mailbox here by that name (#5.1.1)>
Any ideas? I am not finding any errors in the system or application event logs. Among other documentation we have been using this one the most: http://msexchangegeek.com/2010/01/30/rapid-transition-guide-from-exchange-2003-to-exchange-2010/
Also, it might or might be related but the Public Folders from Exchange 2003 are not migrating to Exchange 2010.