We migrated my mailbox from one exchange server to another. My SMTP's are all correct and the mailbox is working fine. However when I go to reply to all or reply to a message that were previously in my old mailbox, I get The message could not be delivered because the recipient's destination email system is unknown or invalid. Please check the address and try again, or contact your system administrator to verify connectivity to the email system of the recipient.
If I freight click on the contact in the TO or CC field and select properties, there are no properties. I made a new prifile, new ost and downloaded address book from the GAL, however I still have the same problem.
Just to confirm that if I pick names of the GAL or reply to new messages there is no problem only when i try to reply to emails that were previously in an old mailbox.