When I send an email message to Yahoo the mail appears to be delivered from my email system but no mail ever appears in the yahoo account. The message appears in the queue and then is sent out of the system. The messages do not bounce back and I do not receive any error codes. I'm using microsoft exchange 2003. I have tested my servers address for relaying through "dnsstuff.com" and no system indicates an open relay. All other smtp mail seems to deliver fine to any other domain (i.e. GMAIL etc..). Here is the response I get in Outlook:
This is an automatically generated Delivery Status Notification.
Your message has been successfully relayed to the following recipients, but the requested delivery status notifications may not be generated by the destination.