fbconnect doesn't login users on my site

I'm a little confused and perhaps there's a simple answer to this but fbconnect login button logs only my application dev account not other accounts.

To explain better:

I do have fbook connect module installed.

I have a 'facebook dev email' that I use for my facebook application, let's call it (dev@gmail.com).
And I have a 'regular facebook user' account, let's call it user@gmail.com.

Now, when I click on the fbook connect button, the registration window pops up.
When I put my dev@gmail.com email, I get logged into fbook as well as to my site. That's great, that's what I want.

However, when I click on the fbook connect button and input my regular user (user@gmail.com) email,
I get logged in to the facebook account within the pop up window, but I don't get logged in to my site.

Any ideas why?

Here's the code fbook connect button code:

<fb:login-button onlogin="facebook_onlogin_ready();" size="medium" background="dark" length="long"></fb:login-button>

Thanks for any suggestions!