Hello All,

My company has 3 sub organizations which run under it. For example My company name is XYZ.com and we have two more sub organisations like abc.com and efg.com. We have exchange server 2010 from XYZ.com. Now i want to configure mail boxes and recipients addresss for abc.com and efg.com. so to achieve this i have created 2 groups in the Domain with the respective names and respective users under each group. i have also created 2 authoritative domains in my exchange server and created default email address policy for each.  When i send mail user1@xyz.com to user2@abc.com, user2@ABC.com is able to receive mails and able to send. Where as if i send mail from external domain i am getting "The error that the other server returned was:
550 5.1.1 Recipient not found." this error. Please help to solve this.