Registering user/site on multisite not working

Hi,

I have just installed my first multisite (followed the manual) and I was testing how can users register their new site and it didnt work.
I have the wp-signup.php page, I can choose to register site or user (I chose site), I can click on continue but when I m done it doesn t send me the confirmation email (I waited 24 hours). I tried with a gmail and also a yahoo email address. I checked the confirmation email is not in the spam folder and also I can`t see any new users or sites as a superadmin on the website.
I have a Contact form plugin on my website and I tested, from that page sending email works fine.

Thanks in advance,
Cecilia