For the SMTP server you need to list one that does not require authentication. If it does then you will not be allowed to send the mail since you are not using any credentials. Based on the value you have posted I would think that this mail server is secured with a password. You should speak with your host about this to confirm the status of the server. If no authentication is required then this should work for the server value. If this is the case then you may be having an issue based on the email address used. Have you tried email address that match your domain and ones that do not? Please post back with what you discover.