1- Is your customization page defined as homepage?
2- Is your customization page defined as one of woocommerce pages?
3- Does the product you are trying to customize exists and is published in your shop?
4- Are you accessing this page from one of the product designer buttons?
https://demos.signsdesigner.us/design-page/design/57/#/
You are trying to access the personalization page without a product to personalize or your permalink is not on postname.
This page should only be accessed using one of the customization buttons.
