Your message did not reach some or all of the intended recipients.

HI we can receive emails but not send. We use outlook 2003. Here is teh error message. Has any seen this before?

You do not have permission to send to this recipient. For assistance, contact your system administrator.

… Relaying denied. Proper authentication required.>

I spoke with the ISP, they say its not them. But something is blocking outgoing mails.