Our email monitoring does not send an email or receive a test email from your mail server. With both our SMTP and POP mail server monitoring basically our monitoring server connects to the specified mail server and does a "handshake" greeting.
If the mail server responds then we report it as up. If there is no response then we alert you that it is potentially down. So this is more then just a ping of the mail server port (110 or 25), we do actually try to communicate with the mail server and get a response. But we are unable to send or receive a test email unfortunately.