Does the failure show up at the "Test Account Settings" point during setup?

If so, I'd suggest altering the server port ID numbers and authentication procedures. You might also find out if there are multiple mail servers maintained by the web host - try an alternative one, especially to send mail. I found that, depending upon the outgoing system I worked on, I had to use a different GoDaddy outgoing server with different authentication protocol ("smtpauth" instead of "smtpout"). I have the occasional problem when traveling that I'm unable to send emails from Outlook through the hotel's system server.