ok checking the same on your site
hi,
please refer to this video:
http://somup.com/cYQ6l6XuHH
as you can see on your site you have enabled the activation email
that's the reason why user is not is activated automatically
once you disable this then the user will be automatically activated on your site
"once you disable this then the user will be automatically activated on your site" how to dasable this option and where?
please check this option:
http://prntscr.com/ufbeus
io have enabled these settings if you enable them it will work same