This article applies to selling in: United Kingdom

Error 18008

Invalid MerchantOrderID. For help on how to proceed, see

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

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