I get an "Property gtin is incorrectly formatted" error
The gtin/mpn property is populated with the barcode or variant_sku options from your shopify store.
Another possible error messages ist "The value of property mpn exceeds length"
You have to make sure these don’t exceed 70 characters in length. Facebook product feed specs say the gtin, mpn or brand property should not be longer than 70 characters.
Also, if you are making use of shopify’s barcode property make sure it is a valid Global Trade Item Number (GTINs). That can include UPC, EAN, JAN, and ISBN.
About GTINs and MPNs in general #
The logic this app uses to map your product/variant information to Facebook’s Product Feed format goes like this
- IF the variant has a barcode field filled out THEN use this barcode as the gtin property in the feed
- IF the barcode field is empty BUT the sku field is filled THEN use this sku as the mpn property in the feed