secureserver.net is the server (at least thats what I think it is....)
Since it can't work without being 100% correct in every setting, your uncertainty would very much seem to be an issue here.
secureserver.net definitely isn't an SMTP server, but it is indeed a bit piece of the name of the godaddy servers
Take the time to read this on that page as well since it certainly won't work if you don't
NOTE: "smtpout.secureserver.net" is an SMTP relay server. In order to use this server to send e-mails, you must first activate SMTP relay on your e-mail account. Log on to your Manage Email Accounts page to set up SMTP relay. If you do not have SMTP relay set up and your Internet Service Provider (ISP) allows it, you can use the outgoing mail server for your Internet Service Provider. Contact your Internet Service Provider to get this setting.
This page is a good run through of the stuff you need, just ignore the IMAP/POP stuff as the printer doesn't need them, only the outgoing stuff applies.
And the printer can only find the latest general release firmwares, not the latest, which is at this moment 68.21.51