Maintenance Work Order Approval Workflow

I navigated in "Manufacturing and Supply Chain Materials Management" and went to the task "Configure Electronic Signature Preferences".

I added the inventory organization and I ticket the checkbook related to "maintenance work order approval". Then I searched for the task "Manage Task Configurations for Supply Chain Management" and created the BMP Approval workflow.

I created a work order. The status of the work order changed from "unreleased" to "pending approval". But the problem is that the approver didn't receive any notification therefore I couldn't approve and continue the workflow.

Here is the the rule created.

Any idea what is missing??