Our mail server supports multiple methods of SMTP relaying and all require authentication. You authentication credentials are your email address and password. We support SMTP submission on port 587 and 25. For reliability, you should prefer port 587, as port 25 traffic is commonly blocked by ISPs, hotels, and most public networks.
username: [your email address]
password: [as assigned]
Use SSL: [yes] 
Requires authentication: [yes]
 If you are using a very old version of Outlook Express (older than Windows XP) or Entourage X (v10.0) that shipped with MS Office X for Mac OS, then you must use port 465. These older clients do not support STARTTLS, which was introduced in 1998. They require the older SSMTP protocol that runs on port 465.
 If you get an error that says you are not allowed to relay, and you have authentication enabled, confirm that you have SSL enabled in your outgoing (SMTP) settings. This is required, else your mail client will send your password across the internet in the clear. We don't advertise the ability to authenticate until after the connection is secured. No secure connection, no authentication.