I've encountered a similar issue before. You might want to make sure that the server is getting the right authentication. Write a small report that just displays the...

Another thing to check; If you're using exchange, or most other SMTP servers, make sure it allows relay from the Report Server.

-Brad

Just a thought, you probably have atleast two options. Either use the webservices and make an app to trigger the reports through the services. The other option is...