relay is open to help you take action to correct this. As the relay on your server is being used to send email by unauthorized users, you would need to close this relay, or enable authentication, so as to prevent this unauthorized relaying.
I am using iis7 php
Once you are done at the “Connections” window, click on OK button to accept the information. Now Click on “Relay” button at the “Access” tab and setup the relay options for the server. Grant the IP’s allowed to relay out mail for the mail server. Make sure “localhost” and IP “127.0.0.1” are granted for relay, addition to that you can also insert your domain name and IP.
would this solve this open relay issue