How to diagnose ActionMailer issues

I’m a bit new on RoR so I might have missed something.
I’ve just installed SaltedHashLogin and even though it works with no
issues, it sends no emails. But I don’t get any errors at all!

I’ve tried the method via the console:
UserNotify.deliver_signup(,"","") and I get the following:
#<TMail::Mail port=#TMail::StringPort:id=0x11f8f20

Are there any logs for RoR or ActionMailer?