Checklist task update and completion Notification to checklist task owner(user)

Summary: I have set up a user as a checklist task owner. In the notification section of the task, I have checked the boxes to send notification to task owner in case of Update and completion of task. The notification however is not triggering to the task owner. Is there an additional set up required?

Content (required):I have set up a user as a checklist task owner. In the notification section of the task, I have checked the boxes to send notification to task owner in case of Update and completion of task. The notification however is not triggering to the task owner. Is there an additional set up required?