Why is Jetpack WorkManager not working at the right time?

Question

Android

I'm trying to trigger timed notifications using WorkManager from Jetpack. Accordingly, I have a Worker class in my application. It accepts the notification title and text as input parameters. The doWork() method describes the logic for displaying a notification. For the health test, I created a OneTimeWorkRequest in MainActivity and queued it for execution. But I can not understand why it is not executed at the right time. I created a date using Calendar, took the timestamp from the date, setInitialDelay specified TimeUnit MILLISECONDS. But nothing works. I will attach the MainActivity and Worker code below
https://pastebin.com/MaW7fdsd - Worker
https://pastebin.com/vEt8ikjc - MainActivity
Any help would be greatly appreciated.