Overview

Error 99021 is a feed submission error in Amazon Seller Central that occurs when a required primary column is left blank while its dependent columns contain values. This validation error prevents product listings from being created or updated until the missing data is corrected. Understanding how to diagnose and resolve this error can save sellers significant time when managing inventory uploads.

Key Points / What Sellers Need to Know

• Column dependency rules - Amazon's catalog system enforces relationships between data fields, meaning certain columns must be filled in whenever related columns contain values.
• Primary vs. dependent columns - A primary column is the main field that other columns rely on. If you populate a dependent column, Amazon requires the primary column to also have a value.
• Feed rejection scope - This error typically affects only the specific rows with missing data, not your entire feed file. Other rows with complete data should process normally.
• Common trigger scenarios - This error frequently appears when sellers fill in variation details without specifying the parent product type, or when optional attribute fields are completed without their required parent attributes.

How This Error Occurs

Amazon's product catalog uses a structured hierarchy of data fields where certain columns depend on others. For example, if you provide a value for a size-related attribute, the system may require you to also specify the size type or classification that governs it. When your flat file or feed submission includes data in a dependent column but leaves the associated primary column empty, Amazon's validation system triggers Error 99021 and rejects that particular row of data. This is a safeguard to ensure product listings maintain consistent and complete information across all related attributes.

How to Fix Error 99021

To resolve this error, start by identifying which row and column triggered the validation failure. Amazon's processing report will typically indicate the column name in the error message, shown as a placeholder reference to the specific field that needs attention. Open your inventory file template and locate the row in question. Check whether the primary column associated with the flagged dependent column has been left blank, and fill in the appropriate value. Once corrected, save the file and resubmit your feed through Seller Central. It is also worth reviewing your entire file for similar gaps before resubmitting, as fixing multiple errors at once will reduce the number of resubmission cycles.