Required identifier (GTIN/UPC/EAN, MPN, or brand+barcode) is absent. TikTok Shop especially requires accurate GTINs for bundles and multipacks.
TikTok Shop / TikTok Catalog Manager uses identifiers (GTIN, MPN, brand, SKU) to match catalog records. Issues come from invalid format (non-numeric in a GTIN field), brand-GTIN mismatches in GS1's database, duplicate IDs across SKUs, or missing required identifiers for the category.