How can I fix 'Missing product data' error in Google Content API feed?

I provide a Content API product feed to Google using the Google sales channel in Shopify.

A few days ago my account was suspended. On the merchant centre overview page I have the error “Shopping ads status: Missing product data”. When I click on Fix Issues I see an additional warning next to products “Product data disapproved”

I’ve had a number of conversations with Google support but they just refer me to their shopping policies document, no-one can tell me what the problem with the data actually is.

Is there some way that I can troubleshoot the content API feed without Google support e.g are there logs I can look at or has someone assembled a list of common mistakes and solutions?

The only way to resolve suspension issues is by checking all policies and ensuring you comply. Google will not give you specifics.

Here is my list: https://community.shopify.com/c/Ecommerce-Marketing/Checklist-Suspended-Google-Merchant-Center-Account-Fix-amp/m-p/1086444/highlight/true#M39128

And I recommend reading:

https://support.google.com/merchants/answer/6363310/follow-the-merchant-center-guidelines
https://support.google.com/merchants/answer/7052112
https://support.google.com/merchants/answer/4752265