530 5.7.0 Must issue a STARTTLS command first

If you are using our email server test tool and you get an error about requiring a TLS command first, it means your server will only accept email over a secure connection.

Our website based testing tool is fairly simply, it just connects and tries to deliver a message. It does not check for encryption or attempts to send encrypted mail, so the testing tool will not work if your server requires encryption in order to accept a message.

Our real email servers will use encryption when attempting to deliver mail.

If you are looking to test the TLS ability of your server you might want to check out http://www.checktls.com.