How to Confirm Your Site is Ready for Google Shopping
When publishing your products to Google Shopping, it is a requirement that the product pages are accessible and meet certain quality requirements that Google imposes, which are:
- Show all key elements of your product
- If linking to a variation, the correct variation must be shown
- The product price must be clearly shown and must match the advertised price
More detailed can be found in this Google help article.
If your site is in pre-release (under construction), protected by password authentication or not publicly accessible, it won't be suitable to use with Google Shopping ads.