The first that you need to do is to check whether you have configured the email server from the Pulseway WebApp -> Server Admin -> Settings -> Email.
And then try to send 'Test Email', to make sure that you have configured the email server correctly. Then if this email is not sent, then please check Log files on your email server or contact your email service provider to find out why these emails are not delivered.
Also, please make sure, that email notifications are enabled for your account. In order to do this open the Pulseway webapp -> Server Admin -> Teams and Users -> All Users -> select the user account and edit settings in Details tab (enable email alerts and notification sending for the users).