do you mean when the new user register on your site, then that email send to the wrong person or you referring the sender email is not correct? If yes, is it possible provide us with your Joomla backend and FTP access at your first post so we can help you check on this?

By the way, we already removed this setting in Easysocial 2.x, now the sender email should refer from your backend > system > global configuration > server > Mail Settings