New Users Not Getting Passwords and Can't Log In

I set up a blog for investing and insurance and whenever anyone (including my failed attempts) tries to add a comment, it says that they have to be logged in. When someone creates a profile:

A) It lets them create it, but then doesn’t email them their password
B) When I went in as the Admin and created new passwords for them, they still couldn’t log in.

I tried switching the theme, but not working.