Shopify troubleshooting library
Start with the exact issue, compare the same product variant across Merchant Center, Shopify, and the landing page, then verify after synchronization. These guides focus on five high-impact errors without promising approval.
Diagnose an exact messageInvalid value [gtin]
An invalid GTIN warning is not a request to fill the barcode field with any number. It means the submitted identifier failed a structural, prefix, assignment, or product-matching check. Start with the exact sellable variant and the manufacturer-assigned code.
Open fix guideMissing value [gtin]
A missing GTIN is an identity check, not an instruction to put any number in Shopify's Barcode field. First determine whether the manufacturer assigned a GTIN to the exact product or variant. Some custom, handmade, vintage, or one-of-a-kind products legitimately have no assigned GTIN.
Open fix guideIncorrect product identifier
This warning often appears when product data says identifiers do not exist even though Google finds evidence that the item has a manufacturer-assigned GTIN, brand, or MPN. Confirm the exact product first; do not toggle identifier_exists only to remove the warning.
Open fix guideMissing value [brand]
A missing brand issue should be resolved with the real consumer-facing brand or manufacturer, not a placeholder such as Generic, N/A, or No brand. If you manufacture or private-label the product, use your actual brand only when it accurately identifies the item.
Open fix guideMissing shipping costs
Merchant Center needs applicable shipping costs and delivery information for the affected products and target country. Account-level shipping policies are usually the starting point; product-level shipping data can override them when specific products have different requirements.
Open fix guideMismatched value (page crawl) [price]
A price mismatch is a consistency problem across a particular offer, not simply a request to type the displayed number into Merchant Center. Compare the same variant, market, currency, sale state, and checkout path at the time Google observed the page.
Open fix guideMismatched value (page crawl) [availability]
Availability errors usually hide at variant level. A product can look in stock while the exact size or color submitted to Google is sold out, unpublished in a market, set to continue selling, or rendered differently to Google's crawler.
Open fix guideProduct page unavailable
A product page can work for the merchant and still fail for Google because the submitted URL is stale, redirects too many times, is unpublished in the target market, requires a storefront password, or receives a different response from bot protection, DNS, or the server.
Open fix guideImage too small
The durable fix is to replace the Shopify source image with an accurate higher-resolution original. Stretching a thumbnail changes pixel dimensions without restoring detail, and Google's conditional optimization does not update the source media or guarantee every image will be handled.
Open fix guideSafe troubleshooting order
A Merchant Center issue names a symptom. The useful work is identifying the exact item and preserving agreement between the source record, submitted attributes, landing page, and purchase state.
Which records and variant states should be compared first.
Where the relevant product, variant, channel, landing-page, or destination setting usually lives.
Which tempting shortcuts can create new data conflicts.
What evidence to inspect after synchronization and recrawling.
A corrected source field does not prove a destination issue is resolved. Processing, crawling, policy, account, tax, market, and destination requirements can still apply. Verify the affected item after Google refreshes it.