You do not have permission to send to this recipient message from Exchange server
Wednesday, November 12th, 2008I had a client yesterday that was getting the following message back from their Exchange server when they tried to send email to anyone outside of their network. They could get receive email and send email internally.
You do not have permission to send to this recipient. For assistance, contact your system administrator. <server.domain.local #5.7.1 smtp;554 5.7.1 <rob@domain.com>: Relay access denied>
I was able to fix this problem pretty quickly by restarting the SMTP service under services in computer management.
They did have to resend any messages that had been rejected.