Navigate to Administration > System Config. Man.
Add the notify.user.before.user.lock.day parameter with a value, in days (notification emails are sent before the defined day value).
Navigate to Administration > Jobs Scheduler.
Open the Trigger List tab.
Select User Notification Before Lock as the Job.
Fill in the Trigger Name and Cron Expression fields.
Select Enabled on the Active to enable the job, field and click Save.