Buy Now button working but not the Add To Cart to buy multiple items

I am using the Parallax theme and the Buy Now button works but customers can’t Add To Cart and buy multiple items. What can you suggest I try please. My store is nearly 7 years old and I am sure it was working and I haven’t made any changes recently so I don’t know why it would now be an issue. It was working on 3rd January. Is there a way to see what changes have been made since then?

Hi @SuzCoolClutch

I understood your concern. I have added the parallax demo theme to my store and I checked that I can add multiple items on click the add to cart button. Please share the URL of the store so I can help you to resolve the issue.

Thank you.