Overview

Error 90186 is a feed processing error that Amazon returns when a product listing submission contains an attribute with a value that doesn't conform to the expected format or accepted options. This validation error prevents the listing from being created or updated until the offending attribute value is corrected. Understanding how to diagnose and resolve this error is essential for sellers who manage listings through flat files, inventory feeds, or API integrations.

Key Points / What Sellers Need to Know

• Invalid attribute values trigger this error — Amazon validates every attribute in your product feed against a set of accepted values, formats, and data types. If any attribute contains a value outside of what Amazon expects, the entire product submission for that item will fail with Error 90186.
• The error message identifies the problem — The error text specifies the exact attribute name, the illegal value that was submitted, and the path within the data structure where the problem occurred, giving sellers a roadmap to locate and fix the issue.
• Common causes include typos and formatting mistakes — Misspelled enumerated values, incorrect date formats, values that exceed character limits, or using text where a number is expected are among the most frequent triggers.
• Category-specific attributes are particularly prone — Different product categories on Amazon have unique required and optional attributes, each with their own set of valid values. Moving listings between categories or using generic templates often introduces invalid values.

How This Error Works

When you submit product data to Amazon — whether through Seller Central flat file uploads, the SP-API Listings Items API, or third-party listing tools — Amazon's feed processor validates each attribute against the product type definition for the relevant category. Error 90186 fires when a specific attribute contains a value that falls outside the acceptable range. The error message follows the pattern: "Attribute '{attribute_name}' has an illegal value '{illegal_values}' in the path '{path}'." The attribute name tells you which field is problematic, the illegal value shows exactly what was submitted, and the path indicates where in the data hierarchy the attribute sits. This structured error format makes it possible to pinpoint the issue without guessing.