PHP List won't send emails

Hi -
I have been trying to get PHPList to send emails for hours. I just upgraded from a fairly old version to the newest one. The database upgrade seemed to happen with no issues and all my data is intact. (And the following problem happened with both the old version and the new version.) When I create a new campaign, I’m able to configure a test email, and when I click to send the test email, it reports back as successful, but I never receive the email. I’ve tried to send to two different email accounts and neither work. I also attempted to send an email to a test list containing only one email address and though it looks like the queue was processed (and the log says that the queue was processed) I never received the email. My host is GoDaddy and I am using phpList version 3.2.6. I’ve never had this problem in the past. I am not using a custom smtp server - I am just using the default settings without having entered any mail servers.