Nav Link to a section


I am trying to link each menu-item from my navbar to a specific section of my MainPage. This is the URL of my website: MainPage

When you scroll down and click on “Shipping”, it will automatically scroll-up and present the “Shipping” section. However clicking on “Billing” section does not work. I can see the URL changing to #billing-section but not working as expected.

Each section div have their unique ID and each item from the navbar link to each section on the page. Can someone please shed some light on what I am doing wrong? Thank you very much,