JavaScript Modal is not automating on Behave with Selenium Web driver

Question

Feature file:

Feature: In order to make a purchase As a visitor; I need to be able to add the item to the cart

Scenario: Adding simple item to cart popup Given I am on a simple item page:/north-shore-night-stand.htm Then I verify the product sku And Verify the product price When I add the item to the cart

Step file: (Only Modal code mentioned attached step fileenter image description here)

Modal attachedenter image description here