Unsupported value due to restricted prefix [gtin]

What this error means

The number in your gtin attribute is structurally valid, but it starts with a prefix that GS1, the organization behind barcodes, reserves for special purposes. Prefixes like 02 and 04, and ranges used for coupons, refunds, or variable-weight goods such as deli items, only have meaning inside a single store. They do not identify a product globally, so Google rejects them.

Why it happens

Store systems and POS software generate internal barcodes in exactly these reserved ranges, because that is what the ranges are for. The problem starts when that internal barcode is exported to the feed as if it were a real GTIN. It looks like a barcode, it scans at your register, but it is not a globally valid product identifier. Weighed products from food retail are the other classic case, since their barcodes encode a price or weight rather than a product identity.

How to fix it

1. Check where the flagged GTIN values come from. If your store or POS system generated them, they are internal codes, not GTINs.
2. For branded products, find the real GTIN on the packaging or from the manufacturer and submit that instead.
3. For private-label or in-house products that have no real GTIN, remove the value from gtin and set identifier_exists to no.
4. Never pad, tweak, or invent a number to get past the check. That converts this error into a mismatch against Google's product catalog.
5. Resubmit the feed.

Fixing it in your store

Keep internal barcodes and feed GTINs in separate fields. Many stores use the barcode field for warehouse labels, and the feed blindly exports it as gtin. Give real GTINs their own field, map only that field to the feed, and let the feed rule fall back to identifier_exists: no when it is empty.

How long until it clears

Expect 1 to 3 days after the corrected feed reaches Google.