I receive the notification emails.

I have tried many times and none seems to work. I have also checked the spam mail and nothing is there. Is there any setting I have missed?

Hi Andrew,
I have found these error exception in the log report:
Mail Exception Occurred. Unable to send mail: Unable to send mail.
#0 /home6/nourishu/public_html/updates/concrete5.5.1/concrete/libraries/3rdparty/Zend/Mail/Transport/Abstract.php(348): Zend_Mail_Transport_Sendmail->_sendMail()
#1 /home6/nourishu/public_html/updates/concrete5.5.1/concrete/libraries/3rdparty/Zend/Mail.php(1194): Zend_Mail_Transport_Abstract->send(Object(Zend_Mail))
#2 /home6/nourishu/public_html/updates/concrete5.5.1/concrete/helpers/mail.php(349): Zend_Mail->send(NULL)
#3 /home6/nourishu/public_html/updates/concrete5.5.1/concrete/controllers/login.php(470): MailHelper->sendMail()
#4 [internal function]: LoginController->forgot_password()
#5 /home6/nourishu/public_html/updates/concrete5.5.1/concrete/libraries/controller.php(213): call_user_func_array(Array, Array)
#6 /home6/nourishu/public_html/updates/concrete5.5.1/concrete/libraries/controller.php(185): Controller->runTask('forgot_password', Array)
#7 /home6/nourishu/public_html/updates/concrete5.5.1/concrete/libraries/view.php(632): Controller->setupAndRun()
#8 /home6/nourishu/public_html/updates/concrete5.5.1/concrete/dispatcher.php(274): View->render(Object(Page))
#9 /home6/nourishu/public_html/concrete/startup/updated_core_check.php(6): require('/home6/nourishu...')
#10 /home6/nourishu/public_html/concrete/dispatcher.php(14): require('/home6/nourishu...')
#11 /home6/nourishu/public_html/index.php(2): require('/home6/nourishu...')
#12 {main}
Template Used: forgot_password

Hope this will help