I completed installing an Exchange 2010 server in an Exchange 2003 environment. I was using one Excahnge 2003 for the company emails. Let's assume my company domain is called abcd.org. After completion of the 2010 server, I moved one user (Let's assume his account is email@example.com). This user can send emails to any internal and external recipients successfuly, but any emaik from inside or outside of the company will not get to his Inbox. Here is the error:
You do not have permission to send to this recipient. For assistance, contact your system administrator.
<jklm2.abcd.org #5.7.1 smtp;550 5.7.1 Unable to relay for firstname.lastname@example.org>
JKLM2 is the name of the 2003 server. The 2010 server is named MNOP2.
Please help me to resolve this problem ASAP.
Thank you all in advance