CMS collection sync Products(ecommerce)

Can each customers create product to Products collection of the e-commerce?

Until now, customers can create and manage CMS collections from the form submission (using Memberstack and Zapier).
But while testing creation of Products collection, keep getting an error saying ‘User is not authorized to perform this action:…’

How can I make the each customers create products to sell ?
Or Is is possible to sync the CMS collection and ecommerce Products?

Thank you in advance for your time to read and for any kind of answers.

Here is my public share link: LINK
(how to access public share link)