Problems between Joomla, Dreamhost and Hotmail

Hi guys!
I’m a new member of this forum!

I use Joomla 1.5 in a Dreamhost’s server. If you want to register in my website, you must confirm subscription clicking on a link that “Chronoforms” send in the e-mail inserted in the registration module.

But all the @hotmail and @live account, don’t receive the confirm e-mail.

PS It’s not spam, the e-mails don’t be sended, They aren’t in the spam folder. Please help me! It’s a great problem!