Follow the steps on this link and you are good - https://www.shafquatarefeen.com/instagram-tag-products-shopify
You would just need one additional step to the ones explained in the link;
Connect your product catalog on Facebook to instagram business account and wait for an approval. This can be done via catalog manager on business.facebook control panel.
I am getting the same problem and even after following lots of tips I have the same error showing in Shopify. I do have policies in place so I am sure I am not violating any of their rules. Can you please tell me what's the best way to get this fixed as well?
I look forward to hear from you.