The Open Relay test can test a particular server for certain known open relay flaws. If you see a Relay Accepted message, you may want to look a little closer at your mail server and the possibility that it could be hijacked to send spam.
If your server tests positive for an open relay, refer to the following article for more assistance:
To test a server for an open relay, perform the following:
1. Enter the server name into the field provided and click Check for Open Relay button.
2. Multiple tests will be performed with the results from each test showing whether or not the relay was accepted.