Hello when someone comments on my post on the wall of the group are not notified by email although I put this function.

Hi,

I made a test, and I can see it the notification under jomsocial mail queue at backend.
if that user still not receive the email, it can be something wrong with that email address or mail configuration at joomla or at server it self.

I suggest to to using SMPT instead of PHPmailer.