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# How to fix common unique identifiers error in Google Merchant Center (Limited performance due to missing identifiers [gtin, mpn, brand])

If you’re getting this error in Google Merchant Center, it means that one or more of your product listings are missing unique product identifiers (UPIs). These identifiers— **GTIN, MPN, and Brand**—help Google properly categorize and rank your products in Shopping Ads. Without them, your ads may still show but with lower performance.

The good news? You can fix this issue by providing at least two of these identifiers. If your product doesn’t have a **GTIN**, you can submit the **MPN and Brand** instead.

### Table of Contents

1. [How to fix products are missing MPN and Brand](#1-how-to-fix-products-are-missing-mpn-and-brand)
2. [How to fix product has no GTIN](#1-how-to-fix-product-has-no-gtin)

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# How to fix products are missing MPN and Brand

### Steps to Fix It

1. **Check with your supplier** to get the correct **MPN** for your products.
    
2. **Go to your Shopify store** and navigate to **Products**.
    
3. **Edit your product variant** by clicking on the product you need to update.
    
4. **Enter the MPN** in the **SKU box**.
    
5. **Save your changes**, and the information will sync into FeedHub and submit to Google Merchant Center.

![1](https://storage.crisp.chat/users/helpdesk/website/ab8a6f89b0a19000/image_zyn3y8.png)

![2](https://storage.crisp.chat/users/helpdesk/website/ab8a6f89b0a19000/image_ylq2kk.png)

# How to fix product Has No GTIN

### Steps to Fix It

1. **Confirm that your product truly has no GTIN** by checking with the manufacturer.
    
2. **If there is no GTIN**, make sure you have both the **MPN and Brand** added to your product details.
  
3. **Update your product feed**  to Google Merchant Center by ensuring the correct fields are filled.
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**Need Help?**

If you run into any issues while fixing these errors, feel free to reach out! Drop us a message in the live chat or email us at [support@socialhead.io](support@socialhead.io). We’re happy to assist!

*Curious to read more? Check out additional articles:*

* [How to fix issue "Invalid sale price" on your Google feed](https://socialhead.crisp.help/en/article/how-to-fix-issue-invalid-sale-price-on-your-google-feed-h2k5tb/)
* [How to solve the disconnected issue on Google feed](https://socialhead.crisp.help/en/article/how-to-solve-the-disconnected-issue-on-google-feed-5xu6ff/)