904 products out of 6000 disapproved. How can I remedy this?

[Mugbarista]

I sell mostly vintage and one of a kind out of print products so they don't have barcodes.  Even if they did have a barcode at one time, there is no way I can determine what it is 99.9% of the time.  So I finally figured out how to get my products listed on Google's free shopping listings.  I used the following feed rule:

This worked great and got over 5000 of my products approved.  However 904 are disapproved with the following explanation:

Even if I enter A GTIN the items ares still disapproved, and for just about all of them I can't find one to input anyway.  Above it says to remove the value, are they saying to remove "Identifier Exists No," if so how?  Isn't leaving that field blank the same thing as "Identifier Exists No?"  I'm so confused,

How do I successfully get these remaining 904 products approved?

Thank you!

[Mugbarista]

I cannot find the GTIN for almost all of the products that Google says one exists for.  The few I can find  I have entered but the products are still disapproved.  I have set identifier exists to no but Google says 904 do exist.

I'm completely stumped on how to solve this!

[Mugbarista]

For anyone else who might be experiencing this problem, I was finally able to resolve it. No amount of tinkering with the built-in Shopify Google channel would resolve it. I finally installed Omega-Google Shopping Feed from the Shopify App Store.  With some assistance from their tech-support, which was excellent, they were able to get all of my products approved and into my Google shopping feed. While it has a minimal cost compared to the free Google shopping channel, I am now confident that all of my products are visible on Google shopping.