I am not sure why but e-mails are not sent to new users. I wanted to send specific email + buddy press message to new users and it seems de-activated ... all other automatic e-mails are working.
I used a plugin to validate users before they get access to the site.
Is there a parameter that disables the e-mails for new users ? I was thinking that maybe when i disabled the plugin the parameter stayed set-up disabling e-mails / new users .