Carrier shipping rates and Google Merchant Center
When using Packrooster Shipping in your Shopify store, there is a valuable thing to take into account. Shipping rate prices from third party carrier apps such as Packrooster Shipping are not automatically synced to Google Merchant Center. This means that if you only use shipping rates configured in Packrooster and you have your Google Merchant Center rate prices on automatic sync, your products are not visible in Google search results because shipping rate prices are required.
The recommended way to solve this issue is by setting up the shipping rates in Google Merchant Center (see here —> Method 2: Set up shipping in Merchant Center)
In this method you deactivate the automatic sync of the Shopify rates to Google Merchant Center and select to manually set up the shipping rates.

After you have manually set up your shipping rates in Google Merchant Center the products will be displayed in the search results.