Alert created successfully - but email not sent on inputted emails

Hi Experts,

I have created an alert for all leaving employees below is the query but while trying to run alert on demand, no email is received. Please advise.

Select  pap.employee_number, pap.full_name, pos.notified_termination_date , pos.actual_termination_date, l.meaning

Into  &E_NO ,

      &E_NAME,

      &NOTIF,

      &ACT,

      &STATUS 

From    PER_PERIODS_OF_SERVICE  pos, 

HR_LOOKUPS  l, PER_ALL_PEOPLE_F  pap

Where   pap.person_id  =  pos.person_id

AND     l.lookup_type  =  'LEAV_REAS'

AND     l.lookup_code  =  pos.leaving_reason

AND     pap.effective_end_date  =  '31-Dec-4712'

AND    pos.actual_termination_date >= TO_DATE(sysdate, 'DD-Mon-RRRR')