Exchange 2k3 NDR Error <mail.com #5.3.5>

Hi,

I have 2 Exchange 2003 servers in a single domain – staff and student. The staff mailing students get an NDR with the following error. Students are able to mail staffs without issues. Please help. Thanks in advance.

A configuration error in the e-mail system caused the message to bounce between two servers or to be forwarded between two recipients. Contact your administrator.