Assign shop, product, my account and checkout page
In order to work our design pages you have to assign shop, product, my account and checkout page.
On your WordPress Dashboard go to WooCommerce >> Settings >> Advanced
If one of the pages do not show up in the dropdown then save click on save and try again.
Go to >>Divi >> Theme Builder
Make sure the shop, cart, my account and checkout page are assigned. Sometimes it can happen that they are not automaticaly assigned.