Overview

Error 99104 is a feed processing error that Amazon sellers encounter when uploading product data through inventory files or feeds. This error occurs when the ASIN value submitted for a particular SKU conflicts with the ASIN already linked to that SKU in Amazon's system. Understanding how to resolve this mismatch is essential for sellers who manage their catalog through bulk uploads or automated feed submissions.

Key Points / What Sellers Need to Know

• ASIN-SKU pairing is locked — Once a SKU is associated with an ASIN in your Amazon catalog, you cannot simply overwrite it by submitting a different ASIN for the same SKU in a feed file.
• Feed rejection is immediate — Amazon will reject the entire record (not just the mismatched field) when this error is triggered, which can delay your listing updates.
• Resolution requires deliberate action — You must either correct your feed data to match the existing ASIN or delete the SKU entirely before reassigning it.
• 24-hour waiting period applies — If you choose to delete and reassign a SKU to a new ASIN, Amazon requires a 24-hour waiting period before the SKU can be resubmitted.

How This Error Occurs

Error 99104 is triggered during feed processing when Amazon detects a conflict between your submitted data and its existing records. Every SKU in your seller account is tied to a specific ASIN, and this relationship is enforced strictly by Amazon's catalog system. When you submit an inventory file, flat file, or API feed that contains a SKU paired with a different ASIN than what is already on record, Amazon flags the discrepancy and returns error 99104. This commonly happens when sellers copy data between spreadsheets, migrate from one listing tool to another, or accidentally edit ASIN values in their feed templates. It can also occur when sellers attempt to repurpose an existing SKU for an entirely different product.

How to Resolve the Error

There are two primary approaches to fixing error 99104. The first and simplest method is to correct the ASIN value in your input file so that it matches the ASIN already associated with the SKU in question, then resubmit the feed. You can verify the correct ASIN by checking your inventory in Seller Central or by looking up the SKU in your Manage Inventory page. The second approach is necessary when you intentionally want to assign a different ASIN to an existing SKU. In this case, you must first delete the SKU from your catalog, wait a full 24 hours for Amazon's system to fully clear the association, and then resubmit the SKU with the new ASIN. Attempting to resubmit before the 24-hour window has elapsed will likely result in the same error.