Hey!
Thanks for your feedback, actually I tried everything and finally I decided to install Abantecart script within last version and rebuild my website from the beginning but, I realized that the same problem is exist too and website does not sending verification emails to new subscribers. Also, I don't know how to upload my backed-up website to server because it has a lot of problems too. those problems i can say them after resolving the website mailer error which we have now.
