I’m experiencing the similar issues.
My site has been published for over a month and I haven’t received any orders. So in efforts to make sure everything was working properly, I clicked on an item to purchase, “add to my cart” button and recieved a message “there are no items in your cart”. How is this possible?
Thanks for reaching out and sorry to hear you're having trouble with your website.
You've reached our Global Seller Community, which is a space for users of Square's POS app outside of countries we service for payments and online stores (US, Canada, Australia, Japan, UK, Ireland). Are you within one of these countries? If not, unfortunately selling online won't be available to you at this time.
If you are, the best place to get help here is to contact support - they will be able to have a look at the back end of your website and determine if there are any issues! You could try unpublishing and republishing the website to see if that helps - however this won't necessarily solve the issue.
If you're in a payments country let me know which one and I'll direct you to the right place!