we have commonal mailbox and user are the member of this mail box with Manage full permission Exchange 2007. Mailbox is Universal---Security group and all user are member of this but still few users are getting this error message.
Delivery has failed to these recipients or distribution lists:
You are not allowed to send this message because you are trying to send on behalf of another sender without permission to do so. Please verify that you are sending on behalf of the correct sender, or ask your system administrator to help you get the required permission
Please help how to resolve this problem
Thanks in Advance.