Wordpress emails not going out


I have been using wordpress for about a month, but I just installed the subscribe2 plugin. I tried subscriptions at a couple of different addresses (incl. gmail and yahoo) to see what the emails looked like, but the emails aren’t being received by the accounts. Then I tried regular wordpress registrations and those emails don’t seem to be going out either, though the admin account (on the same server) is getting notifications.

Any idea what might be going on, or how I could fix it? subscribe2 is sort of useless if people can’t get their initial confirmation emails, not to mention the updates themselves.

I really appreciate any help. Thank you