Can't add a physical product

I'm setting up my store and the only thing left is to add a physical product. I realize there are a few different ways to do this, but I run into the flipping squarespace square (i.e. death spiral) every time I try. The most basic way is to click "Add Product" then "Physical" and it starts flipping forever with the message "creating product..." underneath. I've tried different browsers and get the same message. Any help would be great! Thanks.

This obviously shouldn't happen! It's difficult for forum users to help you troubleshoot this so I encourage you to contact Squarespace directly by raising a ticket through Squarespace Customer Care.