From the Microsoft Dynamics GP Support and Services Blog, Terry Heley tackles a problems where Business Portal 5.0 or 5.1 Human Resources Self Service Suite e-mail notifications are not working
Business Portal 5.0 or 5.1 Human Resources Self Service Suite e-mail notifications are not working – Dynamics GP Support and Services Blog
Payroll & HRMicrosoft & the GP Ecosystem
Archived post from 2011. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.