This article applies to selling in: United Kingdom

Error 18009

Invalid MerchantOrderItemID. For help on how to proceed, see

This error occurs when we are unable to recognize the MerchantOrderItemID you provided. The MerchantOrderItemID must exactly match a value you previously provided in an order acknowledgment feed. Common reasons why this error may occur include:

  • You accidentally provided the AmazonOrderItemID instead of your own MerchantOrderItemID.
  • You transposed or omitted characters in your MerchantOrderItemID.
  • Your MerchantOrderItemID was never created in the system because of an error in a previous order acknowledgement feed.
To resolve this error:
  1. Review you’re the MerchantOrderItemID field. If the AmazonOrderItemID is in that field, provide a valid MerchantOrderItemID. If the field has a typo, correct this.
  2. Update your acknowledgment feed with the corrected MerchantOrderItemID and resubmit your data.
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