I’ve been testing an exchange 2003->2010 migration in my lab. everything goes smoothly till the mailbox move stage. I did some testing after I migrated a couple of mailboxes. I noticed that the emails sent from the newly migrated mailboxes (on 2010) were not getting to the legacy mailboxes (still on 2003). I tried both newly migrated mailboxes to send email to mailboxes on legacy sever but all email are getting queued up on the server. I cannot see any error message on queue viewer as well. so in brief:
– userA and UserB successfully migrated on new exchange 2010 server (mailbox moved)
– userX and userY are still on legacy exchange 2003 server
– userX and userY can send email to each other and userA/userB
– userA and userB can ONLY send emails to each other (all emails to userX/userY are getting stuck in the queue)
what could be the problem here? I’m not sure what is wrong here. any help would be really appreciated.