Is the plugin configured properly?
Yes. I have tried all configurations’ possibilities in it!
Does the user have an email address?
I insert a valid email-address as everything else in register form through the registration. After the Registration, when I search in DB, I can find neither name nor email-address nor the others user’s data.
Is a mail plugin enabled and configured?
Yes, as I mentioned above when I as Master in backend do create a new user, every things works fine inclusive inserting registrant’s data in DB and sending email.