Hello all,
We are migrating few users from one exchange domain to another and we have an annoying problem, let me first give the setup details
New Domain: Abc.com (Exchange 2013)
Old domain: xyz.com(Exchange 2010)
the new exchange server is acting as an external relay to the old domain, the users who have been migrated to the new exchange server have a strange problem, when they send email to anyone in xyz.com, the outlook modifies the email address to @abc.com and eventually receives a non delivery notice because that mailbox does not exist eg if sally@abc.com sends an email to john@xyz.com, outlook modifies the email address to john@abc.com. The users do not have any issuse sending emails to other external domains such as @gmail.com or anything. any suggestion?